diff --git a/av2/common/blockd.h b/av2/common/blockd.h
index 3805e61707..67bd4c293a 100644
--- a/av2/common/blockd.h
+++ b/av2/common/blockd.h
@@ -2331,7 +2331,8 @@ typedef struct macroblockd {
   /*! \brief Flag to decide whether CFL is allowed for a particular chroma
    * block as passed down from the parent tree */
   CFL_ALLOWED_FOR_SDP_TYPE is_cfl_allowed_in_sdp;
-  /*! \brief Flag to indicate whether reduced transform partition mode is on */
+  /*! \brief Flag to indicate whether reduced transform partition mode is on and
+   * is the same as `cm->seq_params.reduced_tx_part_set` */
   int reduced_tx_part_set;
 } MACROBLOCKD;
 
diff --git a/av2/encoder/encoder.c b/av2/encoder/encoder.c
index df551c3cfc..f8791f1ebb 100644
--- a/av2/encoder/encoder.c
+++ b/av2/encoder/encoder.c
@@ -577,7 +577,12 @@ void av2_init_seq_coding_tools(AV2_COMP *cpi, SequenceHeader *seq,
   seq->enable_mhccp = oxcf->intra_mode_cfg.enable_mhccp;
   seq->enable_inter_ddt =
       seq->single_picture_header_flag ? 0 : oxcf->txfm_cfg.enable_inter_ddt;
-  seq->reduced_tx_part_set = oxcf->txfm_cfg.reduced_tx_part_set;
+  // Note: we always keep the sequence header flag `reduced_tx_part_set` off,
+  // ignoring the encoder option `oxcf->txfm_cfg.reduced_tx_part_set`. This is
+  // because the restricting the transform partition types during encoder RDO
+  // only has been found to be more compression-efficient than using the
+  // sequence header option.
+  seq->reduced_tx_part_set = 0;
   seq->enable_cctx = oxcf->txfm_cfg.enable_cctx;
   seq->enable_ibp = oxcf->intra_mode_cfg.enable_ibp;
   seq->enable_adaptive_mvd =
diff --git a/av2/encoder/tx_search.c b/av2/encoder/tx_search.c
index 559c7d1da9..31d3c2b8fc 100644
--- a/av2/encoder/tx_search.c
+++ b/av2/encoder/tx_search.c
@@ -3048,8 +3048,7 @@ static void select_tx_partition_type(
   uint8_t full_blk_skip[MAX_TX_PARTITIONS] = { 0 };
 
   for (TX_PARTITION_TYPE type = 0; type < TX_PARTITION_TYPES; ++type) {
-    if (cpi->common.seq_params.reduced_tx_part_set &&
-        type > TX_PARTITION_VERT) {
+    if (cpi->oxcf.txfm_cfg.reduced_tx_part_set && type > TX_PARTITION_VERT) {
       break;
     }
     // Skip any illegal partitions for this block size
@@ -3362,8 +3361,7 @@ static void choose_tx_size_type_from_rd(const AV2_COMP *const cpi,
   int64_t cur_rd = INT64_MAX;
   const bool is_rect = is_rect_tx(max_tx_size);
   for (TX_PARTITION_TYPE type = 0; type < TX_PARTITION_TYPES; ++type) {
-    if (cpi->common.seq_params.reduced_tx_part_set &&
-        type > TX_PARTITION_VERT) {
+    if (cpi->oxcf.txfm_cfg.reduced_tx_part_set && type > TX_PARTITION_VERT) {
       break;
     }
     // Skip any illegal partitions for this block size