Got a bizarre one which we first noticed with projects since installing 2020.9 and then all further versions since. Which is when we have a project that contains 30p MP4 media that has been AMA'd then those MP4 clips if they have any effects on, wont render.
MC dialog box says x number of effects to render, click ok, and the dialog box disappears and nothing renders
When you position the cursor over a clip, and press the render icon you get a msg PMM_MISMATCH_MEDIA_WRONG_FORMAT
Yet all the clips play fine. You can mixdown or export ok.
If your transcode the clips then all is fine, but sometimes we turned edits round so quick, that there isnt time to trasncode all the media, so we work off AMA most of the time.
Tried all the usual suspects, new user setting, trash mc state, full uninstall reinstall.

Any ideas?

Is it something like render settings set to same as source or something? What if you untick that and set an avid resolution for your renders? 

Andi

You star.

Untick same as source it renders the clips.

Still very wierd that its only does this with 30p mp4 media and only in the last couple of MC versions.

That's so weird that I had exactly this issue the other day (with the same solution). In my case it was with linked UHD p23.967 XAVC-L material in an UHD p23.967 project and for some reason MC thought that it could render this material in the same codec ('as-source')...

Great news! Glad that helped!

Andi