Comment # 15 on bug 1041140 from Mark Gray

I think there is some sort of a race going on between programs using hardware
acceleration on this "oldish" Intel GPU that became more problematic with some
change that was made in the batch of updates that the kernel update was a part
of. The swapping of those two lines of code stood out as a possible culprit,
but as you say should have had no effect. The video of Plasma 5 on 42.2 is
still much worse than 13.2 KDE4 but with compositing turned off the tiny
glitches are only slightly annoying. (I have high hopes for 42.3, and don't
want to waste any more time debugging 42.2 with its EOL coming very soon.)

Thanks for your time.