[Dirt]

Originally Posted by SearChart

Probably extended the crown far enough to engage the intermediate setting wheels, but not far enough to have the balance stopper hit the balance wheel. It happens sometimes.

It's not super common, usually a change of one of the parts (setting lever, setting lever jumper, intermediate setting wheels, minute wheel, stem, balance stop spring) can be enough to never have it happen again.

All parts are manufactured with a tolerance, some spings or gears might be a couple of microns thicker, and some are nicer finished than others when compared to different manufacturing years, etc. Sometimes you get a parts combination and have a glitch like this happen. It's not harmful.

Another example of something similar is when you have a 3185/86 GMT movement (happens on the 3135 as well but much much less common), that when you pull out the crown to the setting position it won't let you, like something is blocking, then after winding and/or quick setting the hour it pulls out to the second position just fine.
What happens is that the 3135-250 intermetiate setting wheels that are in all of the variations of the 31×× series, hit each other teeth on teeth, blocking pulling it out to the setting position.

Great explanation.
Many thanks