the other thing you can do is flatten your paper negative under
something/s that are heavy ... books, sheets of glass &C .. or
if you have a drymount press that is good too
then you just put your flat paper on the unexposed paper
and have no problems at all ...
some people use rc paper for paper negatives
i wonder if they have this trouble too ...

i wouldn't use glue stick or tape ...
it seems like something that had the potential to cause trouble