my $cryptedpass = crypt($passwrd1, $never_blank_value));

Is that a paste from your code? It appears to have unbalanced brackets. Perhaps that's part of the problem?

Alternatively, if you add a diagnostic on such intermittent occurences you might spot a connection. eg:

die "Empty result from crypt($passwrd1, $never_blank_value)" unless de
+fined $cryptedpass;
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