PCRE 7.6 was released on 28-Jan-08. It is now *well* out-of-date. The
current release is 8.30 and there have been many changes to the code in
the intervening 4 years. I am afraid that bug reports for releases that
old are very unlikely to be investigated.
Furthermore, PCRE just does pattern matching. Replacement code is the
responsibility of the application - in this case PHP. To demonstrate
that the problem is in PCRE there would have to be an example that fails
just in matching, not involving replacement.