diff --git a/contrib/amcheck/verify_nbtree.c b/contrib/amcheck/verify_nbtree.c
index 8a642c6e599..0061366dce0 100644
--- a/contrib/amcheck/verify_nbtree.c
+++ b/contrib/amcheck/verify_nbtree.c
@@ -32,7 +32,6 @@
 #include "access/xact.h"
 #include "catalog/index.h"
 #include "catalog/pg_am.h"
-#include "catalog/pg_opfamily_d.h"
 #include "commands/tablecmds.h"
 #include "lib/bloomfilter.h"
 #include "miscadmin.h"
@@ -343,20 +342,10 @@ bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed,
 					 errmsg("index \"%s\" metapage has equalimage field set on unsupported nbtree version",
 							RelationGetRelationName(indrel))));
 		if (allequalimage && !_bt_allequalimage(indrel, false))
-		{
-			bool		has_interval_ops = false;
-
-			for (int i = 0; i < IndexRelationGetNumberOfKeyAttributes(indrel); i++)
-				if (indrel->rd_opfamily[i] == INTERVAL_BTREE_FAM_OID)
-					has_interval_ops = true;
 			ereport(ERROR,
 					(errcode(ERRCODE_INDEX_CORRUPTED),
 					 errmsg("index \"%s\" metapage incorrectly indicates that deduplication is safe",
-							RelationGetRelationName(indrel)),
-					 has_interval_ops
-					 ? errhint("This is known of \"interval\" indexes last built on a version predating 2023-11.")
-					 : 0));
-		}
+							RelationGetRelationName(indrel))));
 
 		/* Check index, possibly against table it is an index on */
 		bt_check_every_level(indrel, heaprel, heapkeyspace, parentcheck,
diff --git a/doc/src/sgml/btree.sgml b/doc/src/sgml/btree.sgml
index 6f608a14bf3..45acb9c4104 100644
--- a/doc/src/sgml/btree.sgml
+++ b/doc/src/sgml/btree.sgml
@@ -846,10 +846,18 @@ options(<replaceable>relopts</replaceable> <type>local_relopts *</type>) returns
    <itemizedlist>
     <listitem>
      <para>
-      <type>text</type>, <type>varchar</type>, and <type>char</type>
-      cannot use deduplication when a
-      <emphasis>nondeterministic</emphasis> collation is used.  Case
-      and accent differences must be preserved among equal datums.
+      <type>text</type> and <type>varchar</type> cannot use deduplication when
+      a <emphasis>nondeterministic</emphasis> collation is used.  Case and
+      accent differences must be preserved among equal datums.
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
+      <type>character</type> (and its aliases <type>char</type> and
+      <type>bpchar</type>) cannot use deduplication.  Trailing spaces are
+      disregarded when comparing two values, but must be preserved among
+      equal datums.
      </para>
     </listitem>
 
diff --git a/src/backend/utils/adt/datum.c b/src/backend/utils/adt/datum.c
index 8708325bdcc..0b91835d192 100644
--- a/src/backend/utils/adt/datum.c
+++ b/src/backend/utils/adt/datum.c
@@ -423,8 +423,8 @@ datum_image_hash(Datum value, bool typByVal, int typLen)
  * function.
  *
  * Earlier minor releases erroneously associated this function with
- * interval_ops.  Detect that case to rescind deduplication support, without
- * requiring initdb.
+ * interval_ops and bpchar_pattern_ops.  Detect those cases to rescind
+ * deduplication support, without requiring initdb.
  *-------------------------------------------------------------------------
  */
 Datum
@@ -432,7 +432,7 @@ btequalimage(PG_FUNCTION_ARGS)
 {
 	Oid			opcintype = PG_GETARG_OID(0);
 
-	PG_RETURN_BOOL(opcintype != INTERVALOID);
+	PG_RETURN_BOOL(opcintype != INTERVALOID && opcintype != BPCHAROID);
 }
 
 /*-------------------------------------------------------------------------
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 257019a3740..8e1354d4f90 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -2881,15 +2881,22 @@ varstr_abbrev_abort(int memtupcount, SortSupport ssup)
 /*
  * Generic equalimage support function for character type's operator classes.
  * Disables the use of deduplication with nondeterministic collations.
+ *
+ * Earlier minor releases erroneously associated this function with
+ * bpchar_ops.  Detect that case to rescind deduplication support, without
+ * requiring initdb.
  */
 Datum
 btvarstrequalimage(PG_FUNCTION_ARGS)
 {
-	/* Oid		opcintype = PG_GETARG_OID(0); */
+	Oid			opcintype = PG_GETARG_OID(0);
 	Oid			collid = PG_GET_COLLATION();
 
 	check_collation_set(collid);
 
+	if (opcintype == BPCHAROID)
+		PG_RETURN_BOOL(false);
+
 	if (lc_collate_is_c(collid) ||
 		collid == DEFAULT_COLLATION_OID ||
 		get_collation_isdeterministic(collid))
diff --git a/src/test/regress/expected/btree_index.out b/src/test/regress/expected/btree_index.out
index c7328b1dc4f..4316565957b 100644
--- a/src/test/regress/expected/btree_index.out
+++ b/src/test/regress/expected/btree_index.out
@@ -266,8 +266,6 @@ select * from btree_bpchar where f1::bpchar like 'foo%';
  fool
 (2 rows)
 
--- get test coverage for "single value" deduplication strategy:
-insert into btree_bpchar select 'foo' from generate_series(1,1500);
 --
 -- Perform unique checking, with and without the use of deduplication
 --
diff --git a/src/test/regress/sql/btree_index.sql b/src/test/regress/sql/btree_index.sql
index c34502249f3..93d35e9dd47 100644
--- a/src/test/regress/sql/btree_index.sql
+++ b/src/test/regress/sql/btree_index.sql
@@ -103,9 +103,6 @@ explain (costs off)
 select * from btree_bpchar where f1::bpchar like 'foo%';
 select * from btree_bpchar where f1::bpchar like 'foo%';
 
--- get test coverage for "single value" deduplication strategy:
-insert into btree_bpchar select 'foo' from generate_series(1,1500);
-
 --
 -- Perform unique checking, with and without the use of deduplication
 --