Jayce R bug.

When you auto attack in cannon form and change forms just at the right time, you will swap to melee form but still hit them with a ranged attack that procs the hammer form passive.

I played Jayce yesterday and a couple times I noticed I was dealing the hammer form passive damage from range while Jayce did the regular hammer form aa animation.

My friend just played Jayce and pretty much confirmed this.

Here's how to do it:

Cannon form auto attack Press R at the right time Hammer form auto attack animation plays Still deal damage Proc hammer form magic damage from range.