[BUG] Deep Remaster and Deep Reference modes both crash; ColorMnet reference mode is OK

[Ricks Film Restoration]

I have a problem with the Deep Remaster and Deep Reference modes; They both crash, but the ColorMNet does work correctly with reference frames.
It happens in step04_muxing: "CRASHED creating mp4 files with mp4box". See attached screenshot. No problem in the ColorMnet reference mode (Method: "RF same as video").
I have two PC's with the same crash problem. Is it maybe caused by improper SETUP whereby the Vapoursyth colorizer overwrites some of the already installed HAVC files?
Should the colorization filter override these pre-existing files or not?

[Selur]

No debug output => nothing I can say.
Since I'll be offline the next few days, best ask here => https://forum.selur.net/thread-3595.html maybe Dan64 can help.

Cu Selur