Bug in RE's?

[Robin Siebler]

I have a list of words that I need to search for in a large number of
files.  I decided to put the patterns into one huge string and make an
RE out of it.  However, at a certain point the RE stops working.  By
this, I mean that the findall method does not return any matches for a
line that contain matches.  If I recompile the RE, it works fine.  the
RE always stops working in the same place and it always starts working
again in the same place.  I have no idea why.  Has anyone ever seen
this?  If this is a bug, where would I report it?