Why is it always April in Mail?

This is a question I asked three years ago and did not resolve. Here is an update.

In my list of emails in the Mail inbox the date always reads 'day, April, year'. It does not matter which month the email was sent, in the list of emails in my inbox the month always reads April, but the day and the year are correct. If you open a specific email the date in the email is correct, just not in the summary list.

This makes it hard to scan down the list and for example find an email that I know was sent in September. I have to stop from time to time, open an email and then see what date it was sent. Close it and move down the list.

I have regularly updated the OS with the latest production version. However the fault remains.

Recently I have purchased a brand new MacBook air, with Apple silicon.

I transferred my existing files to the new machine with Time Machine and all works extremely well apart from the fact that it is still always April in Mail.

I am running macOS Monterey version 12.0.1.

Obviously there must be something in my Mail set-up or Mail files that is causing this error and that it is being passed from one update of the OS to the next, even transferring to the new machine. However I am at a loss as to what in the set-up/files is causing this.

Any ideas?