.mp4 tagged as rec709 showing as Matte in Color Corrector

This seems like someone out there would know what’s going on with this very specific situation.
I’m pulling in a .mp4 file from editorial, it shows as an 8bit clip in the preview. I tag it on import as Rec, but then when I pull it into desktop CC it shows as Matte and gives me a full white frame. I’ve looked in the pref Color management and nothing has been customized. Looks like default setup. I have working colorspace to unknown. I even made a rule so that .mp4 were forced to rec709 on input. The white/Matte only shows up when using desktop CC, desktop diff matte. It works correctly when bringing the same clip into batch, or doing a timeline CC. Any help or input would be greatly appreciated. Thank you.

Mayyyybe Viewer > Show Viewing Settings > Channels > toggle from View Matte to View RGB? I dunno. Sounds crazy.

Thanks, yeah, didn’t think of that. But no, it’s clicked as ViewRGB. There actually is no matte to the clip. It’s just RGB, no alpha.

Flame sometimes borks out when confronted with weird mp4s. Maybe run it through ffmpeg or Media Encoder?

What are you referring to with Desktop CC - the Tools tab? Because you said it works in batch and timeline.

I frequently get mp4’s and png’s that are problematic in flame. I run the mp4’s through media encoder and the png’s through photoshop and all gets put right.

Thanks. Yeah I’ll do that.

yeah, sounds good, thanks.

yeah, tools.