Re: NVDA 2020.3 Beta 4 now available
Replying in the groups.io web editor to test your issues. Firstly, if you installed the beta and didn't intend to, you can either leave it, and it will update to the release candidate(s) as available. Or you can download NVDA 2020.2 again from https://www.nvaccess.org/download/ and install it. The installer will advise that you are installing an older version and warn you against that. I don't think there should be any problem doing that.
To your questions:
1) I'm guessing you can't press escape to go to Browse mode when you are in the editor to write your message? I found in the subject title I could press escape to go to browse mode and enter to go back to focus mode. In the editor, you'll notice NVDA reports "Application". The editor is marked up as an ARIA application - basically it wants to be treated more like a desktop app, so some keys get treated differently. You can still change from browse to focus mode and back using NVDA+SPACEBAR.
2) Reading words twice when they have punctuation at the end. Is that using Chrome? I found in Firefox moving by word skips over punctuation (ie it always jumps to the start of the next word) but in Chrome and other places, the focus moves from the start of the word to in between the word and the punctuation. In Chrome it then reads the word again. I couldn't find an issue for this so I've created one: https://github.com/nvaccess/nvda/issues/11727
3) I couldn't replicate this, but it might be something with groups.io maybe?