updated for version 7.3.1093 Problem: New regexp engine: When a sub expression is empty \1 skips a character. Solution: Make \1 try the current position when the match is emtpy.

end:
2:1
2:17
2:20
3:1
3:17
3:20
5:8
5:25
5:28
6:8
6:25
6:28
8:1
8:9
8:17
8:25
8:27
9:1
9:9
9:17
9:25
9:26