I have a source video clip in the project bin. The source video is about 2 minutes long.

I am using just the last 10 seconds of it, and trying to use the motion: freeze effect in that last 10-second clip.

But when I do this, in the preview window, it is freezing a frame way at the beginning of the source video. It's not even using any frames from the last 10 seconds, which is what I actually have on my timeline.

Any idea why?

This is Kdenlive 19.08.0 on Kubuntu 18.04.

Please try with the current Kdenlive AppImage version 19.08.0a to see if there are any packaging issues https://files.kde.org/kdenlive/release/

If the problem/issue doesn't occur when using the AppImage, then it's your configuration or packaging.

Maybe updating Kubuntu to 19.04 helps as well. (I had a similar issue with Lubuntu)