As a fellow Sony A95L owner, I’ve also noticed that since the June firmware update, the TV no longer automatically switches to Dolby Vision. Sony is aware of the issue, but it looks like we will unfortunately have to wait for the next quarterly update for an official fix.
In the meantime, there is a quick and easy workaround for the latest firmware: when a Dolby Vision video starts playing, simply press the ‘HOME’ button and then the ‘TV’ button on your remote to force the television back to the HDMI port. It works perfectly every time and only takes a couple of seconds.
Ref. Post Vero V Dolby vision broken