Parry (when on mouse 4) does not activate boost on zipline, instead launches off

[PressBtoJump]

I see a few other threads about this, but based on my testing this isn't universal, which is probably why it isn't fixed.

I bound parry to a regular key and it works fine, but with parry bound to my M4 key (which I've used the whole time), rather than boosting on ziplines, you jump off. This changed right on the first 6 hero update patch.