\G problems in 5.10

Dear All,

Is this me or is it a problem in 5.10?

Code that previously worked for me in 5.8 has stopped working in 5.10. The best 
way to show this (not that I have 5.8 now) is that:

perl -e 'use utf8; $t="abc"; pos($t) = 1; print scalar $t =~ m/a\Gb/gcs;'

prints 1 and:

perl -e 'use utf8; $t="\x{1000}\x{1001}\x{1002}"; pos($t) = 1; print scalar $t 
=~ m/\x{1000}\G\x{1001}/gcs;'

doesn't.

TIA,
Yours,
Martin