I don't seem to be able to really fix that gap, at least not to the degree that the clamp is perfectly flush. I think it was exaggerated a bit by a somewhat loose belt. I thought a loose belt would exhibit problems throughout the print, and honed in on the spool issue without realizing it was describing direct drive behavior.
I've got the belt tightened a bit more, and fixed a little bit of wobble in the bed. We'll see if that's enough...
Thanks for the sleuthing and willingness to help!
The glass plate was shifted! Not by the amount the print shifted, but definitely off! I think that means a collision was likely!