Check for Updates?

I've noticed twice that it "seems" that my
Check for Updates only finds new updates when
I update the Portable Apps Menu itself. When I do that
and then do a Check for Updates it finds new updates.
I update all the new apps (Except I keep an old version
of Thunderbird because I like the Penelope Plugin)...
Then after that it doesn't find any new apps until
the next time I update the Portable apps menu (When a
new version comes out)...Has anyone else noticed this?