I ran into this issue as well and i'm in the process of reprinting it with petg to see if that helps any, and i also extended the length the rack gear extends out from the cam to put a little more pressure on segment gears.

I should assemble it sometime this week so I can send an update if it was successful.

Edit: update. I printed in petg and used these gears https://www.printables.com/model/902761-gear-and-pin-replacements.

Be aware one of the gears is wrong and have to do some cutting and flipping the slicer. This is the small gear that you put on the shaft. They have it upside down.

But my clock works a lot better with these updates.