ERROR in attempt to mux (MPLEX)

[Rich86]

BDRB v.5024
I have a BD that I want to make a movie only DVD of.
When I ran it through BDRB, it failed almost at the very end with the error message:
ERROR in attempt to mux (MPLEX)
Here are the last log entries:
[14:59:56]PHASE TWO - Rebuild Started
- [14:59:56] Building ALTERNATE OUTPUT Structure
- [14:59:56] Converting 1 subtitles to DVD format.
- [15:00:41] Starting MPLEX.
- ERROR in attempt to mux (MPLEX)
[15:02:45] - Failed to REBUILD

I noticed BDRB has created a folder under workfiles labeled TMPSUBS which seems to have the english subtitles for the title in there.

I also ran this blu-ray creating a compressed movie-only BD of the title, and that ran fine - english subtitles and all.

Are there some subtitles BDRB is unable to process into a DVD output format?

Update: I still have the movie only BD folders/files created by BDRB from my original BD sitting on my hard disc which included the english subtitles. This ran with no problems and plays just fine. Just for the heck of it, I ran BDRB trying to convert this to a DVD format keeping the english subtitles. It failed in exactly the same way as the previous attempt running off the original files/folders form the original BD. BDRB is able to process these subtitles as long as it stays within BD to BD - but BDRB gags on keeping these subtitles when converting the title to DVD.

Update #2: I ran the original ripped BD through Multi-AVCHD4.1, and it converted the title to DVD including the english subtitles just fine, so I expect something in BDRB is a problem when converting BD subtitles to DVD.

[Rich86]

I just ran into the exact same problem trying to convert my BD of "It" (2017 release) to movie only DVD including the english subtitles using BD-RB 50.25.

Once again, running the ripped files through multiAVCHD 4.1 successfully created the movie only DVD including the english subtitles.

[ScorpionStingz]

It (2017) bd movie only Failed to mux after muxing went to 100% using same version of BDRebuilder. Tried reinstalling everything and have plenty of space.