Minecraft launcher failed to launch after token expiry

My son uses Minecraft Java edition on three devices, two laptops and a desktop. He has a Microsoft account. I have an older Mojang account.

On Sunday (24/01/2021), Minecraft on the desktop suddenly failed to launch, though it was still working for my account and it was working for his account on one of the laptops. Today (25/01/2021) I found out that it was also failing on the second laptop. There was no visible error message or feedback of any kind, it simply seemed to fail to do anything at all.

Having spent some time looking into it I think I've found the cause. It seems that the Minecraft launcher is using XBox live to generate short lived authentication tokens with expiry dates on them. The token in the launcher_accounts.json file had expired. From the logs, I'm guessing that the launcher is supposed to open a login dialog when this happens. If so, it failed.

I've managed to work around this for now by removing the files launcher_accounts.json and launcher_entitlements.json, killing the launcher process from Task Manager, restarting the launcher and logging in. I can hardly expect my 6 year old to do that every time he wants to play.

I've included the logs, the removed files and my system dxdiag report for analysis.