This is not too bothering, but it does not happen on 308 and since I work very often with this setup it prevents me from switching to 311, because that flickering is annoying and distracting.
This is a known bug though in our experience it did happen in 3.0.8f12... at least in some situations.
The team has a beta that fixes it. If you're a beta tester, you can ask for it. Otherwise the fix will be in available in a point release we want to make available as soon as we can possibly manage.