I do not have pcretest, but in my simulated test environment PCRE 8.00 RC 1 does not produce the following result correctly when the pattern *is studied*:
/(\3)(\1)(a)/<JS>
cat
0: a
1:
2:
3: a
With study, the pattern does not match. Without study, the result is OK. It works fine with PCRE 7.9, no matter if the pattern is studied or not.
Ralf