Following up on JavaFan's suggestion, I can reproduce your problem by adding a set of parentheses:
my $regexp = '(\d{4})(\d{2})(\d{2})\s*((\d{2})(\d{2}))';

[download]
Are you sure your production code does not have them?

In reply to Re^2: Simple pattern match failing - Possibly unicode issue by cdarke
in thread Simple pattern match failing - Possibly unicode issue by irahul

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