The text HTML filter has a bug where, when the filter is applied and trimmed the trimming works. If the clip to which the filter is applied is selected after the filter has been trimmed the trimming is removed.
Attached is a project where I applied all 6 html templates to 6 transparent clips. Trimmed each filter to begin at 2 seconds and end at 4 seconds on an 8 second clip. Saved the project. When the project is opened and run in Shotcut all the trims work. If a clip with the text HTML filter is selected the trimming on that clip is removed, the filter on that clip runs for the duration of the clip.
Text HTML Trimming.zip (51.1 KB)