I have not been able to reproduce it. Try the same steps, but do not add it to the Timeline. You do not need to use Timeline or Playlist for a single clip, optionally trimmed.
What is your Windows region setting and its decimal point setting?
Just tested using comma for decimal point in region settings, and that worked for me as well. Please be aware that you cannot write the .stab with one decimal point setting and then change setting and read it. It must be written and read using the same decimal point setting.
I tried it without a timeline and I finally got it to work. When doing that I realized what my error was:
When exporting the video I obviously changed settings like framerate or video size which resulted in an unstabilized video.
When keeping framerate and size exactly to the original numbers, the video will be exported stabilized.
I think I’ll be even more careful in the future when exporting a stabilized video.
PS: I’m working with a German regional setting but I never change that and the regional setting didn’t matter in the end.
I was able to reproduce this as well in Shotcut version 17.09.04 on Windows 7 64 bit by attempting to export 29.97 FPS stabilized source footage at 29.00 FPS. Enabling Parallel processing without changing the export framerate to 29 frames per second does not cause this issue. Modifying the export aspect ratio or resolution also does not seem to cause the issue.
To elaborate on the end result - the exported video that translated around (and/or was cropped) as though it were stabilized, but the video was still visibly shaky, despite the preview of the effect being satisfactory.