This seems to make sense, because this problem seems to always start when using my bluray player, but when I switch source, it doesn't always fix it. Turning off the bose and back on does fix it. However, if I use the bluray player again the green line eventually comes back. On the BR player the 4k upscale is turned off, so it should not be upscaling. I let the TV do the 4k upscaling only. Any device I have connected directly to the TV doesn't replicate the problem. So, at least I do know it's the bose passthrough in some way. Am I missing a setting on the bluray players that could fix this?
Well, I contacted my local Bose rep about it and linked to this page, so hopefully he can figure something out.
However, I did notice that when I do switch the inputs 2 or 3 times as you suggested, the green line eventually goes away for a while. So that was a good tip. Turning the unit completely off and back on was a pain because the Bluray player takes so long to get back up and running with the movie.
Let's see how good Bose support really is.
To early to fully report but, I've found the green line does not appear when i switch off pixel shift on my Tv whilst switching to different resolution (source) through the Bose console, with my Tv being a Oled, this is needed to combat screen burn, I do recall some LCDs also having this option, screen burn can happen on LCDs (image retention) but, has a wider tolerance level than Oled / Plasma.
Have you also tried switching HDMI cable from the Bose to the Tv with a good high speed one, the cable could also cause resolution issues as well. We may be waiting some time for a firmware update 😞