[GNC] Cannot change transaction

[Fred Tydeman]

I am running GnuCash 5.11 on Fedora Linux 41

My default currency is USD.
I have a GBP income account and a GBP asset account.
They are dividend income being deposited into a cash account.
I have existing transactions in those accounts.
I duplicate one of those existing transactions.
I then alter the amount of the dividend.
But, when I click on Enter, or try the Enter key,
nothing happens.
If I try to save the file, I get a popup about unsaved transaction.
If the file gets saved, that transaction is with the old value,
not the value I have tried to change it to.
I have done this in the past with 5.10 and had no problems.
Not sure what I can do to fix this or help debug this.