I'll try to reproduce it and will get back at you. The HPO task (parent of this task) was deleted indeed but that shouldn't matter? One of the models was deleted but the other one wasn't.

Hi @<1631102016807768064:profile|ZanySealion18> , can you reproduce it? This is how it would look if another task that created that models would be deleted

So after publishing a task (right click/Publish from WebUI), one of the models got their id changed to __DELETED__4be00...
The other one (last_model on the screenshot below) is all good and didn't get deleted in this way.
"best_model" exists on the disk and I can access it by taking last_model's URL and just changing the file name, but I cannot normally access it via id (which has now changed to __DELETED__4be00...). Any ideas why this might have happened?