The Side by Side passive is supposed to lower the Cooldown when you use a Melee, Throwing, or Bow attack directly. When you use the Explosive Trap skill directly the Cooldown does not decrease.
Confirmed. Same here. Doesn’t work when Explosive Trap is fired form a Bow either (it is now tagged as a Bow Attack so it should work). I also took the Impact Trigger node in Trap to make it explode on hit and still no CD reduction.
p.s. It works fine for the other Bow Attacks I tried, such as Cinder Strike
Update: Doesn’t work with Net either, which is a Throwing Attack, so it should.