This camera is determined to fight me, I have to say.
Towards the end of the roll, it slipped the film and stopped advancing it. Loaded a second roll to just blast through as a test, and the film counter stopped advancing at 18 shots, though this time the film kept moving. It did this 2 times in a row with the roll.
I was a bit bummed thinking I would have to ship it back to DAG, until I checked out the take up spool more closely; the bottom flange was bent! As the film advanced, the bend was pushing the film out of alignment is all I can guess.
I grabbed a spare spool I bought a while ago, reloaded my tester roll, and 3 times through now it has advanced properly and the film counter has worked perfectly.
I am starting to think this camera is going to be a bit like owning an old axe from grandpa - the shaft replaced 10 times and the head 5.