in reply to Re^2: Using grep and glob to find directories containing file
in thread Using grep and glob to find directories containing file
I think the problem is most similar to the problem of keys (not) resetting the iterator over a hash. I guess that the best solution is to not call glob in scalar context at all.
Most likely, part of the documentation of keys can be adapted to be added to the glob documentation. I would open a bug report using the perlbug utility, best together with a proposed documentation patch that cautions against using glob in scalar context.