I believe it is associated with different screen resolutions - maybe only on Samsung phones(?)…
I can reproduce the effect in either “direction” by changing the resolution.
For example, I was originally on WQHD+ (2960 x 1440), and changed to HD+ (1480 x 720). So, from a higher resolution to a lower one, and the event videos were zoomed in (see previous upload).
I just changed from that lower resolution back up to the higher one, and the image gets smaller. If you think a log file will help I can certainly take one, since i can make it happen by changing resolution.