What happens in a situation like this? Does the staff issue physical keys? Do the doors even have manual locks? Do the staff walk every body to their room?

About a year ago I stayed in a hotel and the door lock started misbehaving one morning while I was at breakfast. Went to the front desk, got a new card, went back to the room and discovered it still didn't work. After doing that two more times, someone was sent up to the room with a mysterious, palm-sized device with a USB cable hanging off it, which they plugged into a well hidden USB port on the bottom of the lock. The device performed some black magic, and after about 30 seconds a light on the lock changed colour from orange to red and it started functioning correctly again.

This also happened on Leap Day 2020 with Onity locks used in Crown Plaza Hotels. See https://i.imgur.com/GI5A3jW.png. I wonder if it's the same issue never fixed? Can you share with us the hotel chain and/or the lock manufacturer? Thanks.