"Invalid signature for profile public key" when connecting to multiplayer world

This bug occurs on 1.19 as well as 22w24a (latest snapshot).

I run a server in my home network. From one laptop, I am unable to log in from one account. I am able to log into the server from other accounts on the same laptop. I am able to log into the server from the failing account on other machines. When I try to log in, the client receives a "Invalid signature for profile public key" error and tells me to restart the program.

I tried:

  - Restarting the launcher.
  - Logging out from the account (in the Launcher) and logging back in.
  - Deleting this Windows account from the machine, and recreating it.
  - Rebooting the machine.
  - Updating Windows.
  - Restarting the server.

The server has a long Java exception trace, boiling down to an InsecurePublicKeyException from a channelRead.

It seems like my client somehow has a bad certificate cached. We ran into this problem before but it seemed to clear away, now it's persistent. Is there some way to inspect the certificate so I can see what's going on?

I want to sort this out because it's my son's laptop and my son's account.