Remember that Batman did tell Cass not to fight metas in her original Batgirl series, and with that kind of tech, Jason is similar to a meta, in that Cass can't necessarily predict everything he'll do.
And I say this as someone who always wants Cass to be the best fighter. I just think that the best doesn't always win - because fights aren't math. Fights are human contact, and thus unpredictable.