diff --git a/rust/plex-pg-core/src/db_interpose_metadata.rs b/rust/plex-pg-core/src/db_interpose_metadata.rs
index d2b8231..ec7f249 100644
--- a/rust/plex-pg-core/src/db_interpose_metadata.rs
+++ b/rust/plex-pg-core/src/db_interpose_metadata.rs
@@ -7,10 +7,10 @@ use crate::db_interpose_common::{
     get_orig_sqlite3_bind_parameter_name, get_orig_sqlite3_create_collation,
     get_orig_sqlite3_create_collation_v2, get_orig_sqlite3_db_handle, get_orig_sqlite3_errcode,
     get_orig_sqlite3_errmsg, get_orig_sqlite3_expanded_sql, get_orig_sqlite3_extended_errcode,
-    get_orig_sqlite3_free, get_orig_sqlite3_get_table, get_orig_sqlite3_malloc,
-    get_orig_sqlite3_sql, get_orig_sqlite3_stmt_busy, get_orig_sqlite3_stmt_readonly,
-    get_orig_sqlite3_stmt_status, get_shim_sqlite3_errcode, get_shim_sqlite3_errmsg,
-    tls_in_interpose_call_ptr,
+    get_orig_sqlite3_free, get_orig_sqlite3_get_table, get_orig_sqlite3_last_insert_rowid,
+    get_orig_sqlite3_malloc, get_orig_sqlite3_sql, get_orig_sqlite3_stmt_busy,
+    get_orig_sqlite3_stmt_readonly, get_orig_sqlite3_stmt_status, get_shim_sqlite3_errcode,
+    get_shim_sqlite3_errmsg, tls_in_interpose_call_ptr,
 };
 use crate::db_interpose_conn_utils::{cstr_to_string_or, log_debug, PthreadMutexGuard};
 use crate::ffi_types::{sqlite3, sqlite3_stmt, PgStmt};
diff --git a/rust/plex-pg-core/src/db_interpose_metadata/connection_state.rs b/rust/plex-pg-core/src/db_interpose_metadata/connection_state.rs
index 9484f28..c65a9ca 100644
--- a/rust/plex-pg-core/src/db_interpose_metadata/connection_state.rs
+++ b/rust/plex-pg-core/src/db_interpose_metadata/connection_state.rs
@@ -48,12 +48,35 @@ pub(super) fn last_insert_rowid_impl(db: *mut sqlite3) -> i64 {
     let pg_conn = crate::pg_client::rust_pg_find_connection(db);
     if pg_conn.is_null() {
         let global_rowid = crate::pg_client::rust_get_global_last_insert_rowid();
+        if global_rowid > 0 {
+            log_debug_lazy!(
+                "last_insert_rowid: CALLED db={:p} pg_conn=NULL (no exact match, global={})",
+                db,
+                global_rowid
+            );
+            return global_rowid;
+        }
+        // Fall back to real SQLite's last_insert_rowid on this db handle.
+        // When the PG path didn't capture the rowid (e.g. the INSERT was
+        // prepared via the real-SQLite path because of stack-depth caution
+        // or because pg_conn lookup missed at prepare time), the shadow
+        // SQLite engine still ran the INSERT and knows the rowid. Returning
+        // 0 here is what makes Plex's SOCI wrapper throw `DB::Exception:
+        // std::exception` every 5s, keeping the server stuck in Maintenance.
+        if let Some(f) = get_orig_sqlite3_last_insert_rowid() {
+            let real_rowid = unsafe { f(db) };
+            log_debug_lazy!(
+                "last_insert_rowid: CALLED db={:p} pg_conn=NULL global=0, real_sqlite={}",
+                db,
+                real_rowid
+            );
+            return real_rowid;
+        }
         log_debug_lazy!(
-            "last_insert_rowid: CALLED db={:p} pg_conn=NULL (no exact match, global={})",
-            db,
-            global_rowid
+            "last_insert_rowid: CALLED db={:p} pg_conn=NULL global=0, no real_sqlite fn",
+            db
         );
-        return if global_rowid > 0 { global_rowid } else { 0 };
+        return 0;
     }
 
     log_debug_lazy!(
diff --git a/rust/plex-pg-core/src/db_interpose_step_write_utils/cached_write.rs b/rust/plex-pg-core/src/db_interpose_step_write_utils/cached_write.rs
index f70e4d0..bde6882 100644
--- a/rust/plex-pg-core/src/db_interpose_step_write_utils/cached_write.rs
+++ b/rust/plex-pg-core/src/db_interpose_step_write_utils/cached_write.rs
@@ -247,6 +247,19 @@ pub extern "C" fn rust_step_cached_write_execute_and_finalize(
                     id_str = id_buf.as_ptr();
                 }
                 if !id_str.is_null() && !CStr::from_ptr(id_str).to_bytes().is_empty() {
+                    // Mirror the non-cached write path (write_exec.rs): publish
+                    // the returned id as `last_insert_rowid` on both the
+                    // executing connection and the global atomic. Without this,
+                    // a cached INSERT with `RETURNING id` produces a row on
+                    // PG but `sqlite3_last_insert_rowid()` returns 0, which
+                    // Plex's SOCI wrapper interprets as "insert failed" and
+                    // throws DB::Exception from every async-task tick.
+                    let rowid = crate::db_interpose_helpers::rust_pg_text_to_int64(id_str);
+                    if rowid > 0 {
+                        let ec = &mut *exec_conn;
+                        ec.last_insert_rowid = rowid;
+                        crate::pg_client::rust_set_global_last_insert_rowid(rowid);
+                    }
                     let meta_id = crate::pg_statement::rust_extract_metadata_id(orig_sql);
                     if meta_id > 0 {
                         crate::pg_client::rust_set_global_metadata_id(meta_id);
diff --git a/rust/plex-pg-core/src/upsert.rs b/rust/plex-pg-core/src/upsert.rs
index 86f770a..b284e0f 100644
--- a/rust/plex-pg-core/src/upsert.rs
+++ b/rust/plex-pg-core/src/upsert.rs
@@ -86,6 +86,45 @@ fn transform_insert(insert: &mut Insert) {
             action: OnConflictAction::DoNothing,
         }));
         insert.or = None;
+    } else if conflict_cols.is_some() {
+        // Plain INSERT into a table where the shim has added a UNIQUE
+        // constraint that SQLite did not have (see plex_schema.sql vs
+        // sqlite_schema.sql for statistics_bandwidth, statistics_media,
+        // metadata_item_settings, etc.). Without this branch, plain
+        // `INSERT INTO statistics_bandwidth (...) VALUES (...)` succeeds
+        // on SQLite (no UNIQUE) but raises `unique_violation` on PG when
+        // the row already exists. Plex's caller does not catch that
+        // and it propagates as `DB::Exception: std::exception`, crashing
+        // PMS — observed on startup roll-up for statistics_bandwidth /
+        // statistics_media on a freshly migrated PG database.
+        //
+        // Use ON CONFLICT DO UPDATE (not DO NOTHING). DO NOTHING returns
+        // zero rows from the trailing `RETURNING id` that
+        // `rust_step_cached_write_build_exec_sql` appends to every INSERT;
+        // Plex's SOCI wrapper expects a row back to populate
+        // `last_insert_rowid()` and throws DB::Exception on the empty
+        // result, leaving the server stuck in startup Maintenance with
+        // an "Uncaught exception running async task" log spam every 5s.
+        // DO UPDATE preserves the row id (RETURNING id returns it) and
+        // overwrites the non-key columns, which matches what Plex would
+        // have done after its SELECT-or-INSERT pattern anyway: store the
+        // latest measurement for this (account, device, timespan, at,
+        // lan) tuple.
+        let columns = insert.columns.clone();
+        let conflict_col_names: Vec<String> = conflict_cols
+            .as_ref()
+            .map(|cols| cols.iter().map(|c| c.to_lowercase()).collect())
+            .unwrap_or_default();
+        insert.on = Some(OnInsert::OnConflict(make_do_update(
+            columns,
+            conflict_target,
+            &conflict_col_names,
+        )));
+        if should_add_returning_id(&conflict_cols) {
+            insert.returning = Some(vec![SelectItem::UnnamedExpr(Expr::Identifier(Ident::new(
+                "id",
+            )))]);
+        }
     }
 }