diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
index ae3a7b6a38..d9840171a3 100644
--- a/src/backend/regex/regcomp.c
+++ b/src/backend/regex/regcomp.c
@@ -1089,11 +1089,23 @@ parseqatom(struct vars *v,
 	/* annoying special case:  {0} or {0,0} cancels everything */
 	if (m == 0 && n == 0)
 	{
-		if (atom != NULL)
-			freesubre(v, atom);
-		if (atomtype == '(')
-			v->subs[subno] = NULL;
-		delsub(v->nfa, lp, rp);
+		/*
+		 * If we had capturing subexpression(s) within the atom, we don't want
+		 * to destroy them, because it's legal (if useless) to back-ref them
+		 * later.  Hence, just unlink the atom from lp/rp and then ignore it.
+		 */
+		if (atom != NULL && (atom->flags & CAP))
+		{
+			delsub(v->nfa, lp, atom->begin);
+			delsub(v->nfa, atom->end, rp);
+		}
+		else
+		{
+			/* Otherwise, we can clean up any subre infrastructure we made */
+			if (atom != NULL)
+				freesubre(v, atom);
+			delsub(v->nfa, lp, rp);
+		}
 		EMPTYARC(lp, rp);
 		return top;
 	}
diff --git a/src/test/modules/test_regex/expected/test_regex.out b/src/test/modules/test_regex/expected/test_regex.out
index 4886858d66..731ba506d3 100644
--- a/src/test/modules/test_regex/expected/test_regex.out
+++ b/src/test/modules/test_regex/expected/test_regex.out
@@ -3576,6 +3576,28 @@ select * from test_regex('((.))(\2)', 'xyy', 'oRP');
  {yy,NULL,NULL,NULL}
 (2 rows)
 
+-- expectNomatch	21.39 PQR	{(.){0}(\1)}	xxx
+select * from test_regex('(.){0}(\1)', 'xxx', 'PQR');
+                 test_regex                 
+--------------------------------------------
+ {2,REG_UBACKREF,REG_UBOUNDS,REG_UNONPOSIX}
+(1 row)
+
+-- expectNomatch	21.40 PQR	{((.)){0}(\2)}	xxx
+select * from test_regex('((.)){0}(\2)', 'xxx', 'PQR');
+                 test_regex                 
+--------------------------------------------
+ {3,REG_UBACKREF,REG_UBOUNDS,REG_UNONPOSIX}
+(1 row)
+
+-- expectMatch	21.41 NPQR	{((.)){0}(\2){0}}	xyz	{}	{}	{}	{}
+select * from test_regex('((.)){0}(\2){0}', 'xyz', 'NPQR');
+                         test_regex                         
+------------------------------------------------------------
+ {3,REG_UBACKREF,REG_UBOUNDS,REG_UNONPOSIX,REG_UEMPTYMATCH}
+ {"",NULL,NULL,NULL}
+(2 rows)
+
 -- doing 22 "multicharacter collating elements"
 -- # again ugh
 -- MCCEs are not implemented in Postgres, so we skip all these tests
diff --git a/src/test/modules/test_regex/sql/test_regex.sql b/src/test/modules/test_regex/sql/test_regex.sql
index 418527da3d..478fa2c547 100644
--- a/src/test/modules/test_regex/sql/test_regex.sql
+++ b/src/test/modules/test_regex/sql/test_regex.sql
@@ -1036,6 +1036,12 @@ select * from test_regex('((.))(\2){0}', 'xy', 'RPQ');
 select * from test_regex('((.))(\2)', 'xyy', 'RP');
 -- expectMatch	21.38 oRP	((.))(\2)	xyy	yy	{}	{}	{}
 select * from test_regex('((.))(\2)', 'xyy', 'oRP');
+-- expectNomatch	21.39 PQR	{(.){0}(\1)}	xxx
+select * from test_regex('(.){0}(\1)', 'xxx', 'PQR');
+-- expectNomatch	21.40 PQR	{((.)){0}(\2)}	xxx
+select * from test_regex('((.)){0}(\2)', 'xxx', 'PQR');
+-- expectMatch	21.41 NPQR	{((.)){0}(\2){0}}	xyz	{}	{}	{}	{}
+select * from test_regex('((.)){0}(\2){0}', 'xyz', 'NPQR');
 
 -- doing 22 "multicharacter collating elements"
 -- # again ugh
diff --git a/src/test/regress/expected/regex.out b/src/test/regress/expected/regex.out
index cbe2cfc3ea..ae0de7307d 100644
--- a/src/test/regress/expected/regex.out
+++ b/src/test/regress/expected/regex.out
@@ -567,6 +567,25 @@ select 'a' ~ '()+\1';
  t
 (1 row)
 
+-- Test incorrect removal of capture groups within {0}
+select 'xxx' ~ '(.){0}(\1)' as f;
+ f 
+---
+ f
+(1 row)
+
+select 'xxx' ~ '((.)){0}(\2)' as f;
+ f 
+---
+ f
+(1 row)
+
+select 'xyz' ~ '((.)){0}(\2){0}' as t;
+ t 
+---
+ t
+(1 row)
+
 -- Test ancient oversight in when to apply zaptreesubs
 select 'abcdef' ~ '^(.)\1|\1.' as f;
  f 
diff --git a/src/test/regress/sql/regex.sql b/src/test/regress/sql/regex.sql
index c6974a43d1..56217104ce 100644
--- a/src/test/regress/sql/regex.sql
+++ b/src/test/regress/sql/regex.sql
@@ -135,6 +135,11 @@ select 'a' ~ '.. ()|\1';
 select 'a' ~ '()*\1';
 select 'a' ~ '()+\1';
 
+-- Test incorrect removal of capture groups within {0}
+select 'xxx' ~ '(.){0}(\1)' as f;
+select 'xxx' ~ '((.)){0}(\2)' as f;
+select 'xyz' ~ '((.)){0}(\2){0}' as t;
+
 -- Test ancient oversight in when to apply zaptreesubs
 select 'abcdef' ~ '^(.)\1|\1.' as f;
 select 'abadef' ~ '^((.)\2|..)\2' as f;