I can't say that has ever happened to me. I only have one profile, and that gets picked before I'm even allowed to look at the videos available, and way before I choose any for download.
Cats4U
I think Peacock, by default, creates an adult and a kids profile. Yes it does ask me to choose at the start of session, but if you leave a session idle long enough, and try to download something the screen is presented again while the analyse progress bar is scrolling, just saying it's happened. In any event, when you are analysing for ages, it's always pertinent to check what the browser window is doing regardless, as sometimes it takes you to the Puss-in-Boots error screen too.
I have made the observation that a lot of content I have gotten lately no longer lists the Bento handler in the video info, but the content is perfectly fine.
Inconsistent audio is a thing, but likely provider related. Ie: Chicago Med S3 has 5.1 @ 384, S4 is @ 192. (unusual for a show to regress)
MrGrackle
I've had Transplant S04 go all AAC until last week and the latest episode, then re-downloaded all episodes of the current season and they ended up being ec-3... not sure what's going on nor where...