Slo-mo videos no longer work correctly on all devices

Yesterday I noticed that new slo-motion video I recorded with my iPhone (13 pro max) is not working properly: it just plays as normal, albeit high framerate video. I then started experimenting and discovered the same issue across all devices (iPhone, Mac and iPad). On my Mac, where I have whole Photos library stored locally I checked several old slo mo videos I know worked ok in the past, and they no longer play as slo-mos. This happens both with slo-mo recorded with iPhone, as well as slo-mos from GoPro.

When I entered into editing mode I still could see and adjust slo-mo range, but after saving, it didn't work. But then I discovered that if I apply any graphics adjustment (color or filter) to the clip, it will save and will start to behave as expected. This will then sync through iCloud and edited clip will start play slo-mo correctly on other devices as well.

Does anyone have similar problems? Can I fill in bug somewhere? It seems it must be a bug: that data itself seem to be all there, its just not displaying properly, and it is exhibited across all devices at once.