If you ever have an issue with a caption of chapter (both use VTT files), here’s the a nice tool you can use to troubleshoot:
webVTT validator - If the code looks good, it’ll tell you! And it is really good and finding persnickety things that are tough for the human eye to find.
As an example, a customer was having trouble having their final chapter appear in their list:
8 00:43:14:000 --> 00:54:11:000 Henry VIII: Second verse, same as the first
Everything seems ok, but the validator gives away the issue:
Almost there! (0ms) Line 32, column 9: No decimal separator (".") found.
Between seconds and milliseconds, we need to replace the “:” with “.”, as shown below:
8 00:43:14.000 --> 00:54:11.000 Henry VIII: Second verse, same as the first
and the chapter appeared as we expected.