When I choose 'Add missing keys' I see this:

Choosing 'Wait' just repeats the message, so eventually one has to choose 'Force Quit'.
 
My system

OS: Linux Mint 22.3 x86_64
Host: Laptop 13 (AMD Ryzen 7040Series) (A5)
Kernel: Linux 6.17.0-23-generic
Uptime: 5 days, 1 hour, 51 mins
DE: Cinnamon 6.6.7
WM: Muffin (X11)
CPU: AMD Ryzen 5 7640U (12) @ 4.97 GHz
GPU: AMD Radeon 760M Graphics [Integrated]
Memory: 5.69 GiB / 14.93 GiB (38%)
Swap: 72.40 MiB / 46.57 GiB (0%)
Disk (/): 20.82 GiB / 147.39 GiB (14%) - ext4
Disk (/home): 62.28 GiB / 384.42 GiB (16%) - ext4
Battery (FRANGWA): 82% [AC Connected]
Locale: en_GB.UTF-8

The system log for at least approximately the relevant period of time contains material about spin locks.

Bugs that might be related

#273;
#1036 (filed against Update Manager).