I am experiencing all the same things already mentioned, but in my case, it may (or may not) be related to Do Not Disturb. I do not use Bedtime to schedule DND, but rather simply have it scheduled as DND: On from 8:00 p.m. to 8:00 a.m., off from 8:00 a.m. to 8:00 p.m. Has worked for years until upgrading from 15.7 to 16.1 on Friday. I had also created wallpaper for lock screen/home screen, and edited from chunky font for time display to thinner, obviously selecting the latter for use. (Kept the orginal unwanted set just in case, as it would be easier to simply modify than going back to wallpaper and starting over in the event it disappeared.
DND malfunctioned immediately following upgrade. It goes on (and, although doesn't always give you the quick notification at the bottom of the home screen, the crescent is displayed above) but often does NOT go off! While on, apparently it chooses to black out the wallpaper selection, which I hate, but this morning, for the first time, it disabled itself on schedule. However - it also immediately switched from my selected wallpaper set in focus to the original chunky font set! It has swapped sets at other times while working on this issue, but unfortunately, I can't be specific - particularly since I didn't realize that was what was occuring. I thought initially that it was simply changing the font.
I believe there is an interplay between DND, wallpaper (as seen in Focus), etc., and am pursuing, although now that it's reaching the engineering level, that usually ends anything productive. I'm glad to have found this discussion, and hope others will continue to post so we might be able to figure it out without the assistance we know won't be forthcoming.