If I SSH to a FreeBSD or Linux (Ubuntu) system and run wish8.6 (tried 8.4, 8.5 and 8.7 on FreeBSD as well) then entry box widgets only allow the letter 'a' to go through.
This can be demonstrated with a trivial wish program, eg..
Then type into the box and see only 'a's go through.
Neither MobaTerm v10.9 build 3656 nor Xming v22.214.171.124 on Windows exhibit this issue.
I am pretty certain this is a regression as I am sure I would have noticed earlier but I don't (yet) have a handle on when it broke - I'll try that next.
I installed 2.7.10 and it worked so I reinstalled 2.7.11 and that worked too so I have no idea!