Preview Pane - content disappearing

Recently upgraded to v8.0.2951 (e2fe9f0). Overall happy with the features and better performance.
Have noticed one peculiar thing that I was not experiencing previously - some (not all) emails once selected in the message list, appear in the preview pane for about 3 seconds - and then the preview pane goes blank. The subject is the only thing left visible, everything else disappears. If you select a different email, then come back to the problematic one - exact same thing happens again.

Same thing happens if I actually open the email - can view it for a few seconds then it vanishes.

Very frustrating. I’m guessing it relates to content of the email. The one giving me issues today has an animated graphic in the body - source of the problem?