I am having strange issues as well...
When I navigate to any thread, only the first few posts load. The last post I can scroll down to only loads part-way, often breaking in the middle of an HTML tag. Then, if I refresh, it loads the whole page. This happens accross several accounts. It does not happen at other phpbb3 forums. I plan on trying from another computer later tonight or tomorrow.
I tried setting my browser to auto-refresh every time I view page but that didn't fix the problem.