I've created 2 tickets with twitch about this and they were both auto-closed and marked as "resolved" and I only got an automated response. Damn useless. I figured that I would try and alert you directly.

When I launch the twitch desktop app, it is set to automatically check for updates and within the past 2 weeks these 3 addons always auto update to the classic wow version of the addon:
DBM
HHTD
Bagnon

I have never had classic installed.

I can tell that they are classic because the version # changes from 8.2.5 to 113.2 (or something like that) and of course the addon throws all sorts of errors if I log into the game without fixing it.

The fix is simple, right click the 3 addons and select Reinstall which puts it back to the correct retail wow addon. It is a bit annoying having to do this. Can you check things from your end to make sure there isn't some kind of incorrect download setting in your twitch project?

We've done everything we could. We provide separate retail and classic builds, but the twitch client appears to have not been properly updated for classic and thus to be buggy.