diff --git a/tsl/src/continuous_aggs/common.c b/tsl/src/continuous_aggs/common.c
index 4efe494a078..bda7ad1bc57 100644
--- a/tsl/src/continuous_aggs/common.c
+++ b/tsl/src/continuous_aggs/common.c
@@ -256,20 +256,31 @@ caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause, List *tar
 				continue;
 			}
 
-			/* Do we have a bucketing function that is not allowed in the CAgg definition */
+			/* Do we have a bucketing function that is not allowed in the CAgg definition?
+			 *
+			 * This is only validated upon creation. If an older TSDB version has allowed us to use
+			 * the function and it's now removed from the list of allowed functions, we should not
+			 * error out (e.g., materialized_only setting is changed on a CAgg that uses the
+			 * deprecated time_bucket_ng function). */
 			if (!function_allowed_in_cagg_definition(fe->funcid))
 			{
 				if (IS_DEPRECATED_BUCKET_FUNC(finfo))
 				{
-					ereport(ERROR,
-							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-							 errmsg("experimental bucket functions are not supported inside a CAgg "
-									"definition"),
-							 errhint("Use a function from the %s schema instead.",
-									 FUNCTIONS_SCHEMA_NAME)));
+					if (is_cagg_create)
+					{
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("experimental bucket functions are not supported inside a "
+										"CAgg "
+										"definition"),
+								 errhint("Use a function from the %s schema instead.",
+										 FUNCTIONS_SCHEMA_NAME)));
+					}
+				}
+				else
+				{
+					continue;
 				}
-
-				continue;
 			}
 
 			if (found)
diff --git a/tsl/src/continuous_aggs/create.c b/tsl/src/continuous_aggs/create.c
index a7e2183fe0b..0b36fbdd7d0 100644
--- a/tsl/src/continuous_aggs/create.c
+++ b/tsl/src/continuous_aggs/create.c
@@ -1026,7 +1026,7 @@ cagg_flip_realtime_view_definition(ContinuousAgg *agg, Hypertable *mat_ht)
 							agg->data.finalized,
 							NameStr(agg->data.user_view_schema),
 							NameStr(agg->data.user_view_name),
-							true);
+							false);
 
 	/* Flip */
 	agg->data.materialized_only = !agg->data.materialized_only;
diff --git a/tsl/src/continuous_aggs/repair.c b/tsl/src/continuous_aggs/repair.c
index 0c355e9379f..400bdb979c0 100644
--- a/tsl/src/continuous_aggs/repair.c
+++ b/tsl/src/continuous_aggs/repair.c
@@ -130,7 +130,7 @@ cagg_rebuild_view_definition(ContinuousAgg *agg, Hypertable *mat_ht, bool force_
 							finalized,
 							NameStr(agg->data.user_view_schema),
 							NameStr(agg->data.user_view_name),
-							true);
+							false);
 
 	mattablecolumninfo_init(&mattblinfo, copyObject(direct_query->groupClause));
 	fqi.finalized = finalized;
diff --git a/tsl/test/expected/exp_cagg_next_gen.out b/tsl/test/expected/exp_cagg_next_gen.out
index ff758c51af7..32dc2be3487 100644
--- a/tsl/test/expected/exp_cagg_next_gen.out
+++ b/tsl/test/expected/exp_cagg_next_gen.out
@@ -196,5 +196,8 @@ FROM _timescaledb_catalog.continuous_aggs_bucket_function ORDER BY 1;
  timescaledb_experimental.time_bucket_ng(interval,timestamp without time zone) | @ 1 mon      |               |                 | f
 (2 rows)
 
+-- Try to toggle realtime feature on existing CAgg using timescaledb_experimental.time_bucket_ng
+ALTER MATERIALIZED VIEW conditions_summary_monthly SET (timescaledb.materialized_only=false);
+ALTER MATERIALIZED VIEW conditions_summary_monthly SET (timescaledb.materialized_only=true);
 \c :TEST_DBNAME :ROLE_SUPERUSER
 DROP DATABASE test WITH (FORCE);
diff --git a/tsl/test/sql/exp_cagg_next_gen.sql b/tsl/test/sql/exp_cagg_next_gen.sql
index bf4396b7c91..769e9729dda 100644
--- a/tsl/test/sql/exp_cagg_next_gen.sql
+++ b/tsl/test/sql/exp_cagg_next_gen.sql
@@ -163,5 +163,9 @@ WITH NO DATA;
 SELECT bucket_func, bucket_width, bucket_origin, bucket_timezone, bucket_fixed_width
 FROM _timescaledb_catalog.continuous_aggs_bucket_function ORDER BY 1;
 
+-- Try to toggle realtime feature on existing CAgg using timescaledb_experimental.time_bucket_ng
+ALTER MATERIALIZED VIEW conditions_summary_monthly SET (timescaledb.materialized_only=false);
+ALTER MATERIALIZED VIEW conditions_summary_monthly SET (timescaledb.materialized_only=true);
+
 \c :TEST_DBNAME :ROLE_SUPERUSER
 DROP DATABASE test WITH (FORCE);