I don't think it appeared before, but I think right now Kaisa is just not having enough tools to shine.
The problem is that her main item - Stormrazor got nerfed.
And with other means she was moved away from meta.
Right now ADC should be bully. Look Jinx for example - quick poke with Q and punish enemy approach with W.
Kaisa just does not have that, it is fully "dive enemy line and die" type of champion.
If you are not allowed to jump, you are kinda useless. Same as Kassadin.
Kaisa and Vayne - both being more of "pure ADC" not lane bullies, struggle in bully-all-in meta.