Even with --ParseSpeed=1, captions are not detected. I've sent you an email regarding...
Captions not detected in some LXF files
I was also able to extract the attached caption data using Telestream Vantage.
I get good 608 captions out when I play it back on an Imagine Nexio NX3601 running...
Also note - the first caption is around 3s from the start of the file.
608 captions not detected (mov container)
LXF container support