[JoeKrepps]

I talked to a pentax rep today. He said it is a known issue of the lubricant of the mirror. If the camera is not used for some time it becomes sticky.
It is similar to the aperture block issue of the K-50 but that was of course a much worse problem. The K-1 problem seems to affects only a few people it seems. I told him I believe another thing adding up might be the battery which is going bad, so there might be a problem to create enough force to move the sticky mirror on the first try.

I asked him if it would make sense to send the camera in to get it fixed but he seemed rather pessimistic on that .

I guess. I mean, geez, nobody can say I'm not getting it out enough if I'm shooting 58k photos in my first year with it. (I wish I was busier. Winter is my slowest time of the year but the slowdown started a good month sooner than usual.)

The faulty lubricant? So far, mine's had a greater problem with hot days, not cold days - I would expect a bad lube to be a bigger problem on cold days but I could be wrong.

VERY disappointing there's no encouragement to have it sent to a repair facility, for a different lube! I guess, in their eyes, "it's just something they do". I do appreciate that you talked to someone. I'm honestly okay with testing it before the 1st photo. It becomes part of the routine of getting my head in the game.Take it out of the bag, turn it On, go through the menus to reformat the cards, check the initial settings for ISO and shutter....and put it in Live View to make sure the mirror is flipping up.
I have to admit, I've had more occasions, in recent weeks, where the mirror did not flip down after a photo. A quick push of the Review button always brings it back down, which is just weird but it works. I won't be happy if it fails altogether but, at least at that point, there should be a definitive fix.
Again, many thanks for checking with Pentax about this! Grateful that you asked and shared their answer.