Many items with conditional bonus weapon damage are not applied on melee based abilities

[fatalfork]

I tested with Billy's Bashdown ability (at rank 3 so it's considered heavy melee), and the following items were not applying any bonus weapon damage on hit

• Close Quarter
• Point blank (the slow effect is applied)
• Opening rounds
• Melee charge (The cooldown is triggered but no extra damage)
• Crushing Fists (The cooldown is triggered but no extra damage, Still apply 2 stacks)

Other sources of weapon damage (such as Berserker) seems to scales the ability correctly.

I get similar results with others heroes dealing melee damage abilities (Bebop, Calico, Drifter, Viscous)