IOS 9.3.5 breaks slow motion video playback - how to fix? I had hesitations about upgrading and just found out that my slow motion videos no longer play back. Displays a white spinner instead. I tried hard reset and recording a new video. No luck

How to make slow motion videos play back on iOS 9.3.5 and iPhone 6s+?
I fixed the issue by recording a new regular video (60 fps) and playing it back. The video plays, and after that slow motion videos play as well. Until this step, slow motion videos displayed a spinner and did not play.