My Roku has stopped going completely to screensaver when video is paused. Instead, it seems to overlay the Logo Rain screensaver over the paused video, usually flickering between the paused image and the screensaver's black background, sometimes popping back and forth between that combined image and the paused video alone. It's like the screensaver isn't completely kicking on.
It started on HBO Max, so I assumed it was an issue with that channel. It's now doing it elsewhere too, though, and sometimes with the selected 'inactivity' screensaver (not Logo Rain) as well.
I've seen only one other mention of this issue, but that was on a different forum and no solution was offered, so I've tried things I've seen suggested for similar-sounding issues: - The Roku's been restarted, used with a different HDMI cord, different TV and different WiFi (I took on a wee vacation) and it produced the same problem. - I changed the display type to 720p. It did stop HBO's half-second buffering at the start of shows, but not the screensaver's seizures. - I changed the default screensaver, even though Roku doesn't use it, to see if it 'resets' the behavior. Still flickers. - I changed the screensaver start time. Still flickers.
I saw suggestions to change the frame rate to fix a flickering video issue, but that's not an option for the Roku 3 .
I may have solved your problem (or at least one of your problems) as I too have a Roku 3 and had issues with HBOmax and most other channels (except for Netflix and Hulu), and I was able to fix this issue, which I posted on another forum that had a link to this forum. I do use my Roku Ultra (2018) instead of my Roku 3 to watch movies on the HBOmax channel, so I'm unsure if this will completely fix what you're experiencing with having to go to 720p as a workaround, but that issue might also be resolved if it's related to the micro-SD card you could be using in your Roku 3. People forget all about the micro-SD card that's in older models, which ends up causing various problems since the cache of the SD card conflicts with newer updates -- it really slowed my Roku 3, and I was able to solve that speed issue as well, as now it's as peppy as my Ultra.
If this does help to resolve your issue and you know of other threads/forums with people who have this glitch then feel free to post this link to them if it's relevant.