In my collection, I have exactly one game that has AVI cutscenes: King's Quest 6 CD. For a laugh, I copied HDLOGO.AVI to my SCI Companion scratchpad and removed most of the logo stuff from the title screen, repalcing that with a simple
ShowMovie(0 "hdlogo.avi"), then restoring the usual palette in the next state and all that. That works, no problem. So I made it play TOON.AVI, confirming that Media Player Classic doesn't like MS Video 1 files with (certain kinds of) palette changes.
Turns out ffmpeg can't encode to MS Video 1, but luckily I have content creation programs that can export to AVI, including the option to use MS Video 1...
Unknown tag '....' found!
Oh. What '....' though? There's no such thing in this file, as far as I can see.

Fun exercise: look closely at the JUNK chunks in KQ6CD's HDLOGO.AVI file.