I thought I could check $&, but it's zero length every time through the loop. I don't understand why that is, because it's supposed to give the last successful pattern match, and there are successful matches in every case except the second.
The g modifier seems to be clearing $& (or maybe it never gets set in the first place). Add re to your code and you should see the match be successful at first, but it ultimately fails: 
use re 'debug';

[download]
In any case, the g modifier is probably doing you more harm than good. Perhaps a more knowledgeable monk can elaborate on what's going on here. Further reading:

In reply to Re: Determing if this regex matched by toolic
in thread Determing if this regex matched by cormanaz

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