AFAIU the problem is at Modules/_sre.c:852: after matching, if the ptr is still at the start position, the start position gets incremented to avoid an endless loop.
Ideally the problem could be avoided by marking and skipping the part(s) of the pattern that have already been tested and produced a zero-length match, however I don't see any easy way to do it.
Unless someone can come up with a reasonable solution, I would suggest to close this as wontfix, and possibly add a note to the docs about this corner case.