I can't run many tests right now, but what you describe sounds like a side effect / evaluation order problem with using this special variable multiple times inside the same statement.

(Similar with using func($x++,$x--) where the evaluation order is undefined and aliases are passed)

Splitting the statement into multiple ones with just one postmatch should fix it.

I'll try later...

Update

See Re^2: ${^POSTMATCH} problem

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re: ${^POSTMATCH} problem by LanX
in thread ${^POSTMATCH} problem by pl_pm

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