Solving playback issues

[mangosmoothie]

3930RW Roku Express
X004006MXPT4
Software 11.5.0 build 4312-AE
ID T4-198-586

Steps to reproduce:
Turn "Auto-adjust display refresh rate" to ON.
Open the Haystack News channel.
Watch a video from some source, say, ABC News.
Switch to fullscreen.
The video plays correctly in fullscreen mode.
Watch a video from Euronews.
Switch to fullscreen.
The video shrinks to the upper left corner of the screen. The rest of the screen is black.

Turn "Auto-adjust display refresh rate" to OFF.
Repeat the steps with Haystack News and watch the same videos.
All videos display in fullscreen mode correctly.

Power cycling does not help. Euronews videos on Haystack consistently have this problem.
The issue also happens with certain videos on the Prime Video channel, for example "The House on Mansfield Street". The TV is set at 1080p. I have not tested 720p.

I found many topics with problems related to this setting and a couple related to the video shrinking instead of being in fullscreen, but none linking the two.

I don't need help resolving this problem. Leaving the setting disabled is OK with me. I'm just reporting the issue and how I worked around it.

[Anonymous]

Does your TV display any PAL 50p content correctly? Might be a limitation of your set, in which case "disabled" is the correct setting.

[mangosmoothie]

The most official set of specs I can find do not mention PAL, so likely not.

Regardless, the behavior of the Roku in such cases is not user-friendly. PAL vs NTSC is not a thing many people consider with new digital TV's and streaming services. This particular setting is tucked away from other display settings, and I had forgotten it existed.

If this is the cause, the ideal behavior when this set of conditions occurs is to fallback to the "native" refresh rate, so the viewer isn't wondering why their video and app interface are shrunken into a small box. One might just assume the channel itself is broken.