If this were a US major, CPSC would force a recall. Trek recalled a whole years worth of bikes because a loose front skewer lever could get caught up in the disk rotor. LOL. If they weren't forced to use lawer lip washers, the wheel would have have fallen out and that would never happen. I think Trek either put on a new skewer with a shorter lever, or they flipped it to the other side.
Now that I see the pictures, look like the center tube was just too weak. Snapped off an inch or more below the weld.
There's really too many chinese ebikes coming in with frames that are copies of copies, with no engineering. I've seen a couple of other folder frames that snapped and the importer discontinued that model. Another major importer had a half dozen threaded steerer tubes snapping off.