Sometimes non-scaling title clips in 720p/1080p projects

For quite some time I'm now fighting with kdenlive in my attempt to change the rendering profile of several existing projects from 720p to 1080p resolution. My raw video footage is actually of 1080p resolution so this would make sense for me.

The project was originally done as 720p/25fps; in particular, all title clips were created while this project setting was active.

My problem now is: in several project, the title clips do NOT scale, but in other projects they do when I switch the project from 720p/25fps to 1080p/25fps. Even within the same project, some title clips scale, others not.

What is really strange: when I edit such a title clip, I get a warning that it is of different resolution, but when I also enable displaying the background, the scaling is fine in the title editing dialog. However, when viewing in the project monitor, the scaling of the title clip is wrong.

Is there any way to rescale an existing title clip?? I'm totally lost...

Okay, finally found the cause of the problem and could solve it: while the title clips were okay, the transitions (composite) were errorenously scaled down to 66.67%. So I had to manually check all transitions (composite) and reset them to 100% -- unpleasent work, but finally my project is now 1080p. Phew.