xLights draws a face that doesn't exist

[deonb]

On one of my sequences, xLights draws the face below. I don't have a face looking like that...

It's drawing it on "Face Main" on this xgbeffects - you can see it doesn't have a layout like that:
https://www.dropbox.com/sh/3hi9jyz92kvpnx1/AACiXLyeoFhl8hVadDoqtF2Oa?dl=0

I've tried deleting my .fseq's and RenderCache and restarted xLights, but it will re-render it like that again. I can't see how though.

I can share the sequence privately that causes the problems as well if a developer needs it (let me know how), but don't want to post it publicly since it's based on a paid Lilia sequence.

[Gilrock]

I would suspect there is something causing the render buffer to get squished like altering the render buffer size in the black area of layer settings or rendering as part of a larger model group.