I came back to the game last week and my house was fine up until today when it started doing this. I tried everything to sort out a fix, but nothing works. Restoring an old back up does nothing, nor does the fix for corrupted data. I'm not sure why this is happening. The EHT is blocking out everything around it as you move, even though its been perfectly aligned. Just seems so weird its happening as I haven't even done any editing to the house since I came back.
Not an expert in these things but when things started to go pear-shaped for me it was resetting my screen size settings in game which sorted it. Hope that works for you.
So I checked last night to see if it was the Subsamling quality, but that was already set to high. The culprit was having my setting to full screen instead of full screen/window mode. So it's back to normal now.
It is also worth noting that some computers (mine included) have a fancy enough nvidia card that they auto opt you into something called DSR. I found out, belatedly, that that kept readjustng my resolution, and that caused me loads of problems for a while. If you're among those with this problem, check your display settings, then the 'manage' option, and uncheck anything that says dsr.