diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 46f45f6654..6ae02056d7 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -4655,6 +4655,8 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 	FormatNode *n;
 	NUMProc		_Np,
 			   *Np = &_Np;
+	int			separator_len;
+	bool		noadd;
 
 	MemSet(Np, 0, sizeof(NUMProc));
 
@@ -4808,6 +4810,7 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 	 * Locale
 	 */
 	NUM_prepare_locale(Np);
+	separator_len = strlen(Np->L_thousands_sep);
 
 	/*
 	 * Processor direct cycle
@@ -4819,6 +4822,7 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 
 	for (n = node, Np->inout_p = Np->inout; n->type != NODE_TYPE_END; n++)
 	{
+		noadd = false;
 		if (!Np->is_to_char)
 		{
 			/*
@@ -4879,6 +4883,10 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 								continue;
 						}
 					}
+						if (strncmp(Np->inout_p, Np->L_thousands_sep, separator_len) == 0)
+							Np->inout_p += separator_len - 1;
+						else
+							noadd = true;
 					break;
 
 				case NUM_G:
@@ -4890,10 +4898,8 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 								continue;
 							else
 							{
-								int			x = strlen(Np->L_thousands_sep);
-
-								memset(Np->inout_p, ' ', x);
-								Np->inout_p += x - 1;
+								memset(Np->inout_p, ' ', separator_len);
+								Np->inout_p += separator_len - 1;
 							}
 						}
 						else
@@ -4909,7 +4915,10 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 							if (IS_FILLMODE(Np->Num))
 								continue;
 						}
-						Np->inout_p += strlen(Np->L_thousands_sep) - 1;
+						if (strncmp(Np->inout_p, Np->L_thousands_sep, separator_len) == 0)
+							Np->inout_p += separator_len - 1;
+						else
+							noadd = true;
 					}
 					break;
 
@@ -5030,7 +5039,8 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
 			if (Np->is_to_char)
 				*Np->inout_p = n->character;
 		}
-		Np->inout_p++;
+		if (!noadd)
+			Np->inout_p++;
 	}
 
 	if (Np->is_to_char)
diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
index ae0beb9b68..41b582de09 100644
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -1925,3 +1925,36 @@ SELECT SUM((-9999)::numeric) FROM generate_series(1, 100000);
  -999900000
 (1 row)
 
+--
+-- Tests to regression test TODO item 'Fix to_number() handling for values not matching the format string'
+--
+select to_number('34,50','999,99');
+ to_number 
+-----------
+      3450
+(1 row)
+
+select to_number('34,50','999G99');
+ to_number 
+-----------
+      3450
+(1 row)
+
+select to_number('12,34','999G99');
+ to_number 
+-----------
+      1234
+(1 row)
+
+select to_number('123,000','999G');
+ to_number 
+-----------
+       123
+(1 row)
+
+select to_number('123456','999G999');
+ to_number 
+-----------
+    123456
+(1 row)
+
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
index b51225c47f..e1dd3a405c 100644
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -1005,3 +1005,13 @@ select scale(-13.000000000000000);
 -- cases that need carry propagation
 SELECT SUM(9999::numeric) FROM generate_series(1, 100000);
 SELECT SUM((-9999)::numeric) FROM generate_series(1, 100000);
+
+--
+-- Tests to regression test TODO item 'Fix to_number() handling for values not matching the format string'
+--
+
+select to_number('34,50','999,99');
+select to_number('34,50','999G99');
+select to_number('12,34','999G99');
+select to_number('123,000','999G');
+select to_number('123456','999G999');