Potential damage bug [Gameplay]

So I was just playing an ARAM for fun. Was dying more than normal at first (no this isn't a qq post and we did eventually win this game). I'm checking the "death recap" and it keeps saying different characters did "true damage" and nothing else. I mean characters that don't have true damage, and in sizeable amounts.

Like for example one time it said darius did 62% of the damage or something like that, and then it says Jax, true damage, 38%. It doesn't say how either or what ability.

Anyways, I don't know how to really test this to know if it's a problem with the death recap, masteries or runes not applying, or some kind of in game damage bug, but I thought I would bring it up just in case. I don't know what causes it either. Definitely was not noticing it before. So, who knows?