My understanding is that in actual use for technical climbing, ropes do no typically break at the knots. Most often the rope is cut by being stressed across a sharp rock edge, etc. or fails at a point weakened by abrasion or something similar. Unfortunately, I am unable to cite any recent analyses. Does anyone have current info?

At least my ropes have not broken, at the knots or anywhere else, for that matter.

The only example of rope breakage in my experience was the deliberate sacrifice of a 9mm climbing rope to extricate a vehicle from a flooding stream. With abuse like that,it was not surprising when it popped. It did not break at the knot, as I recall.