diff --git a/core-tests/e2e-tests/spring/spring-rest-openapi-v3/src/test/kotlin/org/evomaster/e2etests/spring/openapi/v3/httporaclefp/partialupdateputfp/HttpPartialUpdatePutFPEMTest.kt b/core-tests/e2e-tests/spring/spring-rest-openapi-v3/src/test/kotlin/org/evomaster/e2etests/spring/openapi/v3/httporaclefp/partialupdateputfp/HttpPartialUpdatePutFPEMTest.kt
index e8dba5d009..07b9a213f4 100644
--- a/core-tests/e2e-tests/spring/spring-rest-openapi-v3/src/test/kotlin/org/evomaster/e2etests/spring/openapi/v3/httporaclefp/partialupdateputfp/HttpPartialUpdatePutFPEMTest.kt
+++ b/core-tests/e2e-tests/spring/spring-rest-openapi-v3/src/test/kotlin/org/evomaster/e2etests/spring/openapi/v3/httporaclefp/partialupdateputfp/HttpPartialUpdatePutFPEMTest.kt
@@ -8,7 +8,6 @@ import org.evomaster.e2etests.spring.openapi.v3.SpringTestBase
 import org.junit.jupiter.api.Assertions.assertFalse
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.BeforeAll
-import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 
 class HttpPartialUpdatePutFPEMTest : SpringTestBase(){
@@ -21,8 +20,6 @@ class HttpPartialUpdatePutFPEMTest : SpringTestBase(){
         }
     }
 
-    //FIXME: fails due to missing "hidden" not ignored as not defined in schema of GET
-    @Disabled("Currently failing, as revealing a bug in the code")
     @Test
     fun testRunEM() {
 
diff --git a/core/src/main/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracle.kt b/core/src/main/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracle.kt
index b0736b5e4d..3564cccad3 100644
--- a/core/src/main/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracle.kt
+++ b/core/src/main/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracle.kt
@@ -346,9 +346,13 @@ object HttpSemanticsOracle {
             return null
         }
 
-        val wipedFields = computeWipedFields(allPutSchemaFields - sentFields, schema, get)
+        val getSchemaFields = extractGetSchemaFields(schema, get)
+        val comparableSentFields = if (getSchemaFields.isEmpty()) sentFields else sentFields intersect getSchemaFields
+        val wipedFields = if (getSchemaFields.isEmpty()) emptySet() else (allPutSchemaFields - sentFields) intersect getSchemaFields
 
-        val mismatches = mismatchedPutFields(putBody ?: "", getBody, sentFields, wipedFields, bodyParam)
+        if (comparableSentFields.isEmpty() && wipedFields.isEmpty()) return null
+
+        val mismatches = mismatchedPutFields(putBody ?: "", getBody, comparableSentFields, wipedFields, bodyParam)
         if(mismatches.isEmpty()){
             return null
         }
@@ -391,21 +395,18 @@ object HttpSemanticsOracle {
     }
 
     /**
-     * Wiped candidates are restricted to fields the GET schema actually exposes, otherwise
+     * Sent and wiped candidates are restricted to fields the GET schema actually exposes, otherwise
      * write-only fields (e.g. passwords) would cause false positives.
      */
-    private fun computeWipedFields(
-        candidates: Set<String>,
+    private fun extractGetSchemaFields(
         schema: RestSchema?,
         get: RestCallAction
     ): Set<String> {
-        if (candidates.isEmpty() || schema == null) return emptySet()
-        val getSchemaFields = SchemaUtils.extractResponseSchemaFields(
+        if (schema == null) return emptySet()
+        return SchemaUtils.extractResponseSchemaFields(
             schema, get.path.toString(), HttpVerb.GET,
             statusMatcher = SchemaUtils.statusGroupMatcher(StatusGroup.G_2xx)
         )
-        if (getSchemaFields.isEmpty()) return emptySet()
-        return candidates intersect getSchemaFields
     }
 
     internal fun mismatchedPutFields(
diff --git a/core/src/test/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracleTest.kt b/core/src/test/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracleTest.kt
index 68997021f2..12ae5e943d 100644
--- a/core/src/test/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracleTest.kt
+++ b/core/src/test/kotlin/org/evomaster/core/problem/rest/oracle/HttpSemanticsOracleTest.kt
@@ -647,6 +647,51 @@ class HttpSemanticsOracleTest {
         assertFalse(mismatch)
     }
 
+    @Test
+    fun testPut_sentWriteOnlyFieldNotInGetSchema_noFalsePositive() {
+        val schema = buildUsersSchema(
+            putWritable = listOf("name", "hidden"),
+            getResponseFields = listOf("name", "timestamp")
+        )
+        val mismatch = runMismatchedPutOracle(
+            path = "/users",
+            putBody = jsonPutBodyParam(activeFields = mapOf("name" to "Alice", "hidden" to "secret")),
+            getResponseBody = """{"name":"Alice","timestamp":"123"}""",
+            schema = schema
+        )
+        assertFalse(mismatch)
+    }
+
+    @Test
+    fun testPut_sentWriteOnlyFieldNotInGetSchema_exposedFieldChanged_returnsTrue() {
+        val schema = buildUsersSchema(
+            putWritable = listOf("name", "hidden"),
+            getResponseFields = listOf("name")
+        )
+        val mismatch = runMismatchedPutOracle(
+            path = "/users",
+            putBody = jsonPutBodyParam(activeFields = mapOf("name" to "Alice", "hidden" to "secret")),
+            getResponseBody = """{"name":"Bob"}""",
+            schema = schema
+        )
+        assertTrue(mismatch)
+    }
+
+    @Test
+    fun testPut_allSentFieldsWriteOnly_returnsFalse() {
+        val schema = buildUsersSchema(
+            putWritable = listOf("hidden"),
+            getResponseFields = listOf("id")
+        )
+        val mismatch = runMismatchedPutOracle(
+            path = "/users",
+            putBody = jsonPutBodyParam(activeFields = mapOf("hidden" to "secret")),
+            getResponseBody = """{"id":"1"}""",
+            schema = schema
+        )
+        assertFalse(mismatch)
+    }
+
     @Test
     fun testPut_putReturnedNon2xx_returnsFalse() {
         val mismatch = runMismatchedPutOracle(