I've noticed that I dont receive some emails if they're filtered at source (moved from inbox into separate folder)

Happens with both my BES account and hotmail accounts

Has anyone else noticed the same and is there a cure?

I know only that with BIS, the push email comes only from the inbox, so hotmail items moved from inbox to another folder, won't get pushed.

But with BES, your supposed to have the folders you use, and therefore mail should be received in them. Its possible though that it will just download it into that folder and not notify you of it.