@zing Tried with a clean install of 8.1.1 and had the same issues.
But one thing that call my attention was I have some "under voltage" warnings (I have the NesPi case with a official power adapter from Rpi) that on previous releases were noticed when I turn off the system, but in this release I think the loss of signal maybe are correlated with this alerts.

Same issue here.... RPi3B, SD 64GB. Occurs mostly on the emulationstation interface and with SNES emulation.