I don't recall having any of that with my GTX570 and later 580 setup but it does happen with the AMD cards, 290 and now Fury X. By the the way, I just dropped in a used GTX570 I bought off eBay and the combination with the Fury X really rocks! I can now finally use MC AVC again and render at lightning speeds!
We have discussed that in our German Videotreffpunkt.com forum too. It seems to happen only when the GPU acceleration in the preview is enabled. If you disable that then the bypass for left/right works.
Seems to be a bug caused by later drivers required or Windows 8, 8.1 and 10 (I have not seen that with Win7).
Same is true for the out of sync of the video/audio stream that has been shown in red. Seems to be also a driver issue beginning with Windows 8.
WS : "It seems to happen only when the GPU acceleration in the preview is enabled. If you disable that then the bypass for left/right works."
Exactly, so by turning off one Feature - GPU ACCELERATION - we get to operate another, to my mind that means a Bug and needs squashing.
I can confirm this bug on WIN7 64 bit using R9 280 GPU and the latest build of everything relevant. GPU rendering in Vegas is dysfunctional to such extent that in >90 % of the cases you must turn it off, for various reasons. Sad, sad story...
Sorry, my bad wording... I ment preview, even though the real rendering (out) has its issues too... Actually - converting video originating from the original but encoded video source material (into the preview window) can be called rendering since its a process converting from one format to another... But agreed, we should be consistent in the usage of terms. My mother tongue is not English so pardon me for the unintended confusion.