5.2.10 - odd behavior- page outputed twice

Hello, i am confronted with odd behavior of php 5.2.10. I compiled and packaged the same way like other prior versions. If i install 5.2.10 and reload page (sefrengo cms) the page is outputed completely twice.when scrolling down i see same page again incl. <doctype <html> </html> etc. Downgrading to 5.2.9 solves problem and page looks like intended. somebody has already heard of problems like this? i do not really know in which direction to look, current buglist contains no fitting descriptions.. i guessed a relation to bug #48994 but was not confirmed, also current 5.2.11rc2 showed odd behavior. Any ideas? Thanks, Andre