BlueTracker

I believe you're referring to the simple tooltip not referencing that enemy Heroes need to be hit to increase the Fan of Knives damage?

In that case it's not necessarily a bug. We refer to the tooltips that talents show before you take them as Simple Tooltips, which are intended to be a super high level view of what the talent does. We have a goal of generally keeping these tooltips to one line, with some rare exceptions to go slightly to 2 lines. If you look throughout the game you'll find tons of cases like this. Another example just on Tracer is that the simple tooltip on Tracer Rounds doesn't reference that her Basic Attacks only reveal enemy Heroes.

In order to keep these tooltips short and to the point we also sometimes don't reference all of the functionality of a talent on these simple tooltips, but only the more gameplay defining portions of the talent.

Still, feel free to report this on the Bug report forums, as this one could be better. If I had a second go at it i'd probably have the simple tooltip be something like: "Damaging Heroes increases Fan of Knives damage"

Bwahaha it's been a long week.

Will fix.