[TYPO3-dev] Weird caching problem?

[Christian Lerrahn (Cerebrum)]

Hi,
I have a weird problem with an extension I've just written. The
extension displays a form and then might react with the same form again
but fill the markers in the form template differently. The extension is
set to USER_INT in its source code.

Now the weird problem I have, is that when I submit the form, TYPO3
renders only a blank page. It is not an empty page but just one with an
empty body. If I clear my caches and reload the page, I get the right
kind of data in my form (as a reaction to the re-sent post). However,
if I reload again, I'm back to the blank page. What is happening here?
All PHP errors should be displayed (I've switched on everything on my
dev system) and how would it be possible to produce a valid page on one
occasion and then an invalid one with exactly the same data?

Any ideas anyone?

Cheers and TIA,
Christian