Maryland Quarter With Mad Reverse

I agree. it might be a partial collar. (that is what it looks like from the image)

There is nothing stopping an uncentered broadstrike from having partial contact with the collar, which may have been only partly deployed. And the collar contact I see is brief indeed. Is the coin presented here exactly the same diameter as a "normal" Quarter? If not, then it has not been fully constrained by the collar and is therefore, by definition, a broadstrike. It certainly looks to have far more "space" added to the left side (the "broad" one) than subtracted from the right side.

Interesting. Is the reeding you showed in your pic the only reeding on the coin, or how complete is it? A collar is required to force the final diameter to exactly Quarter size, and if the collar is holding it, then it should be reeded. Note, the diameter difference could be pretty small.

Furthermore, if the reeding isn't present in some location, that should be where the coin's diameter is allowed to increase. A partial collar will still constrain a planchet, but at that point some metal should spill over the area where the collar can't hold it, much like foam from a beer you poured too quickly.

So, I should expect the reeding to be pretty much complete on the right side of your coin, and nearly absent on the left. Weak on the right, possibly, because there isn't "pushback" from the left side to force the planchet against the reeding, but present. Both faces are pretty accurately struck, implying the dies were correctly located relative to each other, so the only "error" here seems to be with the collar.

And - correct me if I'm wrong - it's how "present" or not that collar is, which is the dividing line between "partial collar strike" and "broadstrike." What I cannot define is whether or not a broadstrike requires complete absence of the collar, or not. I don't set those definitions.

Fun coin.