iPhone repeatedly asks for passcode to unlock.

Hi, 

I have received a message 3 times in the last week saying: "your passcode is required to unlock iPhone". Why am I getting this? 

I also get a message every day that I need to enter my passcode to activate FaceID. 

I know someone will respond with the usual text from apple that is saying:

• The device has just been turned on or restarted.
• The device hasn’t been unlocked for more than 48 hours.
• The passcode hasn’t been used to unlock the device in the last six and a half days and Face ID hasn’t unlocked the device in the last 4 hours.
• The device has received a remote lock command.
• After five unsuccessful attempts to match a face.
• After initiating power off or Emergency SOS by pressing and holding either volume button and the side button simultaneously for 2 seconds.

None of these is true. My phone has been laying on a table all day. I entered my code 24 hours ago. The phone has not been restarted, and FaceID has not been activated. So why am I getting this message?

I found a Reddit thread with that same problem that doesn’t answer the question: https://www.reddit.com/r/iphone/comments/1qhzf3r/why_does_it_sometimes_say_your_passcode_is/