Solution found! I think we have the same issue, symptoms are the same except I noticed it only happens when on battery power. I did 2 things, but I think the second one is all that is needed. If it doesn't work alone, than do the first also.
1) Rollback intel 550 driver to the one in July in device manager. October one is the current one.
2) Open Intel Iris Graphics Control Panel. Choose Power > On Battery. Disable Panel Self Refresh.
Stopped flickering as soon as I did this. Let me know if it works.