Thats good advise Peter.

I just tried to answer PM from Bran
I used the 'quote button' to read it as message was blank.
Replying with her quoted message caused it to be blank also.
So I started a new PM (but copied and pasted my previous message) and this didnt work.
Then I typed fresh message....via the 'quick reply'...and blank!
The next attempt, going to full 'reply' worked.

I will send report and hope it helps crazy