Just wondering on the Model 17 issue,,when the problem happened, did the shooter attempt to open the action using the slide latch?
That should have released the action to be opened w/the hammer cocked ,,regardless of wether there was a case in the chamber or not.

I've had the short stroke issue occur on a Win97 a few times of late. Just me doing it, nothing mechanically wrong with the gun.
It will leave the fired case in the chamber & on the 97 recock the hammer to 1/2 cock. That puts me out of commission and I have to open the action using the slide latch button.

I'm sure other hammerless actions can do the same,,others not. They're all a bit different. I use a number of pump guns and all will act a bit different if short stroked. Some will eject the empty and then just dump the next live round right out the port onto the ground.
I've had a Rem17 in the past and can't recall having the issue,,but I was younger and stronger then!

Never had a 29,,quite a number of Model 10's though. I found them nice shotguns dispite the bad press they get. At least the bad rap made for good buyers prices. Gotta know what you're looking for in them though.