Embedded Closed Captioning Out of Sync on Export

seems like a long shot, but figure it's worth mentioning as when there are synch issues the source of the problem is often clips with a variable frame rate which usually occur in screen recordings and material shot on a smartphone.  If so, post back and I'll give you the lowdown or just do some searching here on how to fix this.

I know this is not a longterm fix, but I think I've found a workaround. If you export the sequence as MXFop1a with a .mcc sidecar file, you can take these two files and load them into a new sequence in premiere. When you export from that new sequence and choose to embed the captions in the output file, the captions should be at the right framerate/timecode in the final .mxf file. As others have mentioned in this thread, you can check to make sure that the captions are lined up properly by loading the final caption-embedded .mxf file into a new premiere sequence. This is a much more time consuming process than it should be, but it seems like I'm not losing any data in the process as the size of the output files remains the same. 

I'm having the same issue. I've been using Premiere to export TV broadcast for the past 2 years and had zero issues with Premiere until the 15.0 update. I'm also using Windows 10 and exporting a MXFop1a file. The same thing happens where the captions get out of sync and the caption file itself ends 15 minutes early even though it should be 58 minutes long. It does the same thing even if I export a small segment of the file. 

I've tried many different solutions, including trying Drop Frame or Non-Drop Frame captions.  The only work around I can find is to use Premiere Pro 2020 (version 14.9). I have no issues whatsoever with that version. Hopefully Adobe can figure out what went wrong with the update because it's cumbersome to edit in 15.0 and then import into 14.9 to export to broadcast. I'm glad I'm not the only person with this problem. I've been searching for solutions for the past few weeks!

How do you test the playback of the mxf embedded file? I have had trouble finding a good external playback, so can only test by importing the file back to PR.

I assume the out of sync shows on import back to PR.

I'll try to test this. I am now on 15.1; also Win 10.

Stan