I upgraded my firmware last week to the latest for DJI Pilot 2, Batteries, and the P1.

I was flying a photogrammetry mission with the P1 35mm and had "Calibrated infinity focus" selected in my mission planning, rather than "First point autofocus" and as expected, the flight began with infinity focus. I noticed, however, that after a few seconds it had adjusted to 1 tick down, so I moved it back to infinity. It would then adjust to a new value a minute or two later. It ended up that I had to babysit the focus wheel for the 70 minute flight, although I did not notice the issue at all in the back half of the flight. I did not touch the screen at all after the first few minutes of the flight.

My hunch is that when you tap the screen to switch to live view, or look at any menus, the touch is also initiating the autofocus behind the buttons that you are touching.

Has anyone else experienced this? Hopefully an update including this patch is released soon.

The problem has already been reported, it is also present on L1 and M3E.
Ryan H. Thanks for reaching out, and apologies for the inconvenience. We will forward your concern to our team for confirmation. Thanks for your understanding.

That's done.  Moderator, no need to thank me. If there is anything else that we can help with, please let us know here. We appreciate your support and understanding.

Most definitely this is a reoccurring issue across many DJI products I've found. The M3E is so bad about changing manual focus by itself. Usually it's like you just said, focus will change by one tick down. Just last week though for the first time I witnessed the focus change FOUR notches down from infinity when I was 75% through a mission. I was in disbelief. So much so that I repeated the mission 2 more times while screen recording thinking that I'd for sure catch the M3E red handed. As you can probably guess it never happened again. I have brought this up before and it is yet another issue that DJI ignores, won't address, and pretends as if it doesn't exist.

Any update on how to keep the M3E from defaulting to Manual focus mode?