This looks like a bug, though it seems to be an older one relating to 5.6. That it breaks on a multiprocessor system but works on a uniprocessor makes the likelihood of a bug much higher. Please consider reporting to http://bugs.perl.org.

Googling for that error message also revealed one or two comments about people avoiding "shift" in certain circumstances back in 5.6. You might see if that helps.

-xdg

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In reply to Re: bizarre Carp by xdg
in thread bizarre Carp by gjh

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