Deduplicating and identifying the source of a crash point is surprisingly hard, to the point that “it’s the only crash of its kind” could be a bug in your logic for linking issues.

This is a bit vague to really reply to very specifically, but yes, this is hard. Which is why quite some people work in this area. It's rather valuable to do so at Firefox-scale.

Even if the majority of time it generates the “same” failure mode, it can still sporadically generate a rare execution trace.

This doesn't matter that much because the "same" failure mode already allows you to see the bug and fix it.