Just took a look and PUW movements in general has a crown wheel with a small bearing. And by the looks of your ratchet screw I would say it is missing the small bearing and is upside down.
I just pop a picture on a common PUW ratchet wheel here so you can see what it might look like.
Crown wheel of course.... screw has no shoulder probably the washer was then lost.
I am learning... very slowly... went to bed 4:15 this morning. I was shocked by the result after the cleaning i guess i must pay the price of the knowledge. Very painful so far and not much knowledge gained, well to my former myself i go with lightspeed but it is just not enough and they say there is no 2 x lightspeed.
1-Imperfect hairspring coil can foul itself when amplitude gets too high so the rate goes fast , until such time that HS coil jumps back to normal.
2- Loose and pushed back guard pin, fails to guard the roller table- impulse jewel properly, in which case if the balance wheel gets in a hurry on wrist it is susceptible to the condition in section 1.
Faulty guarding by the pin, can let the condition for sticking to come about.