self.nextsort = self.win.getSort() - 1000
This line (which occurs in 2 places in the file!) causes post processes to render before the window renders the texture they are supposed to use. This causes, for example, a 1 frame lag if you enable a filter, like bloom.
The post processes should have a sort higher than the window right?
I noticed this issue since I was getting mixed frames (my deferred shaded stuff was off by one frame from the forward shaded parts of the scene). I increased the sorts and it fixed my issue. My use-case is not quite the regular use, so I may be missing some detail.