This just started happening for me yesterday (link to video). I move from one slide to the next, and there is an afterimage of the previous slide that slowly fades out. This is particularly noticeable with white background slides such as hymn projection, but it's there to one degree or another all the time.
It is only on my main displays. Confidence monitor and OBS don't have this issue.
What I've tried so far:
-Checked for updates to proclaim and imac (both fully up to date)
-swapped out HDMI cables/changed ports
-Rebooted everything
-changed display settings to default
-Factory reset the TVs
