It worked, because you had Applied the Modifiers.
Before Applying the Subsurf, you might have had something like this:
You could also have matched the Levels of Subdivision for Viewport and Render, instead of Applying the Modifier.
But maybe, as you say there is more to why it didn’t work for you. The file you sent worked out of the box (of course you re-Baked, after Applying the Modifiers, right?).
The 0 Frames on disk in your video are still a bit suspicious.