Typewriter effect causes error message

I’m trying to use the typewriter effect in a title clip for the first time. When rendering, I get the following error:

[mp4 @ 0000021c8564a040] Timestamps are unset in a packet for stream 1. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly [mp4 @ 0000021c8564a040] Encoder did not produce proper pts, making some up.

The resulting video seems to play OK, but it’s only a few stills with fades between them at the moment.

If I turn the typewriter effect off, it works fine.

Any ideas?

Which version of Kdenlive, which OS, and which installation method would be a good start for troubleshooting …

24.08.3 on Windows 10, using the install version.