tvOS 12 broke HDMI to DVI connection to 23” Apple Cinema Display

I have 3x AppleTV Mk4 connected to (Aluminium) 3x Apple Cinema Display 23” (HD 1080p) for which I stream various news channels, football and so on. the displays have DVI and are connected to appleTV via DVI-HDMI adaptor. All fine and historically never had any issues ... until last night.

Updated to tvOS12 on one and appeared to be all fine except I got a blank screen. no amount of restarting etc. Fixed the issue. So whilst I was pondering this the screensaver cut it displayed on my screen (when previously I thought it was bricked). However as soon as i clicked on the remote, it went black (I could the remote working as the light flashes on the Apple TV)

So I connected the AppleTV to a regular HD 1080p TV i.e. direct HDMI cable and it was all fine - 100% working fine.

So I updated another APpleTV to tvOS 12 (thinking that perhaps the issue was specific to the appleTV). Unfortunately exactly the same thing.

BTW the apple cinema displays are absolutely fine and are working 100% (as tested it with non-upgraded appleTV)

So the issue appears to be that the AppleTV (V12) doesn’t like connecting to a DVI monitor via an adapter. I saw on that V12 has a new feature (HDMI Check Cable) but I have no idea what this is whether related to the issue or not.

I managed to restore both appleTVs top 11.4.1 (usb-c cable and iTunes + download of v11.4.1 separately) and both now are back to normal and just fine.

Therefore the issue is with tvOS 12 where it doesn’t like DVI monitors and/or HDMI-DVI adapter.

Has anyone else had this issue? (As I would like to update to 12 but not at the cost of normal functionality!!) or is there workaround (other than restoring to 11.4.1 which I did )

thanks in advance