Some Chapter Markers Do Not Export Chapter Name

I just finished exporting a project in which I had placed 5 Chapter Markers on the timeline. In the exported .m4v file, the first 4 Chapter Markers contained the chapter names I had specified, such as “Welcome,” “Speaker,” “Q&A”.

The last chapter is named “Credits”. In the exported .m4v file this displays as “Chapter 5” in QuickTime Player, though it appears correct both in the Timeline Index and in the Creator’s Best Friend FCP extension. In the Apple TV app, the last chapter doesn’t even appear in the chapter menu, and in VLC the last entry in the Chapter menu is shown as
??Mol$mJ?#????<??rK?DCQ4.

I’ve experienced this in other FCP projects, too. One recent project contained 20 Chapter Markers. When I opened the exported movie in QuickTime Player, the first 17 had correct chapter names. The last three had names “Chapter 18,” “Chapter 19,” and “Chapter 20”.

Any idea what’s causing this to happen, and how I can cure the problem?

Thanks!

FCP 10.6.5
2023 M2 MacBook Pro
macOS Ventura 13.0