Gangplank, Ezreal, and Miss Fortune's Q's do not calculate damage correctly.
"Gangplank shoots a target enemy with his pistol, dealing physical damage. This ability can critically strike and applies on-hit effects, including Grog Soaked Blade."
I will use gangplank as my example, but its the same with all 3 champions. This spell says it will critically strike and applies on hit effects, great, additional damage. But, it does not count as a spell.
Therefore there is a bug, that doesn't count these three spells as actual spells.
If they work as intended, fine, change the description.
Fizz's Q is the same but it clarifies that spell effects will still proc, although its a spell, so this is redundant information.
"Fizz dashes a fixed distance in the direction of the target enemy unit, dealing 100% AD physical damage plus bonus magic damage. The physical damage applies on-hit effects and the magic damage applies spell effects."
Please edit the game to state that their 3 abilities do not in fact count as spells for some reason.