I have 5 roku devices, tcl roku tv, roku ultra 4600x, 4800, 2 4820 , all of are on 14 and updated.
When setting the backdrops, settings, select what one's I want to use, set backdrops to start in 30 minutes, 1 minute to change, the settings do not hold and revert to 10 minutes to change., go to the bottom of the app, set this again, same issue, if I select the star menu button, it shows the picture timeout again to 10 minutes again.
I have a screen saver set for 5 minutes and no issues with that.
I don't have an old TV, but I also don't want to get a burnt image either.
I have disabled the backdrops until a fix can be done