I have the latest version of Synthesizer V Studio Pro. When extending the last note (the “oh” in measure 76) any amount earlier than the start of measure 76, or deleting this note, the editor seems to delete everything after measure 25, and no sound is rendered at all. Saving the project in this state causes it to also be loaded in the same state. This doesn’t seem to happen with other notes, however.
The forum won’t allow uploads of .svps for some reason, so here is the project: Stars T2.svp - Google ドライブ It’s currently in a good state, but editing the last note will cause the bug.
This .svp was probably originally made with an earlier version of Synthesizer V, around December 2021, and I just opened and edited it today.
Note #86 looks suspect, as it has a negative duration - which perhaps not coincidentally is the negative value of the onset:
It also looks like note #87 is overlaying note #86, as they have the same offset:
If you’ve got a decent text editor (like Notepad++), you could open the file, search for the incorrect duration of -211680000000 and replace it with a duration of 2822400000 (a quarter note), that should fix your problem.
For goodness sake, whatever you do, don’t use Windows Notepad to do the editing!