Huge HDMI issues in this beta: Can't output 4K to my TV anymore; sound cutting out in 1080p; flashing image (TV keeps switching between 1080p and 1081p‽). All things that were working perfectly in the first two betas.
Basically almost impossible to use with any reliability.
EDIT: It seems to be related to Thunderbolt power management? Everything seems to work as normal when only the HDMI converter is connected, but if my FW 800 - TB converted hard drive is also connected sounds starts cutting out again. This wasn't a problem previously, so something must have changed in this or previous beta.