The fix that I use is a pain, but it works: I unplug both the power and the other cable from my 4k pvr for 10 seconds, then hook them back up. In about a minute, the tv is fine again, and stays fine the entire time you watch.
Im having the same issue with my Vizio 70". Cant even tell you how many times Ive contacted Rogers on this with no resolution. Im so incredibly frustrated because its been fine for 2 years and now for the last 5 months its unusable. Especially given that we are all home now, not having the service work is so so frustrating!!! I am at the point where Im ready to go elsewhere...Im tired of the non answers Ive been getting