May be some settings in LAV? Problem on connection stage.

It seems to be the "Delay playback until render queue is full" setting in MadVR, disabled that and it's gone.

Is it working now?

Yeah it's working fine now

MadVR showing as installed on 7.35.9! One thing i have discovered is if you set ProgDVB to use GUI for OSD when using MadVR channels change aspect ratio automatically when needed but you can’t change manually. Whereas if you have it set to not use GUI you can manually change aspect ratio but it doesn’t change automatically when needed. MadVR never uses the HD OSD skin but i have read that its a MadVR bug