Vicious Projectiles Support interaction with melee skills that spawn projectiles (Molten Strike)

Set up a Molten Strike skill, supported by Vicious Projectiles Support. Molten Strike has two options on the left panel, Melee Hit and Magma Balls. When you switch between these options, Magma Balls is affected by the Vicious Projectiles attack speed penalty, and Melee Hit is not, even though it's impossible for these to have two different attack speeds in game.

In game, the attack speed is not affected by Vicious Projectiles. The tooltip damage is not affected either, but I don't know if that affects the projectiles. So I don't know if the support gem is actually free damage on Molten Strike, or if it has no effect, but it definitely doesn't affect the attack speed.

Reproduce the issue with Molten Strike supported by Vicious Projectiles, switching between the Melee Hit and Magma Balls options. Trace the projectile and attack-speed calculations from the relevant skill and support-gem entry points, which are not named in the report. Done means the two Molten Strike options agree with in-game attack-speed behavior and the support gem's projectile damage effect is correctly represented.