Tristanna jump unstunnable

I'm a support main and I've main Leona and it's starting to annoy me because I keep stunning Tristannas non-stop but no matter what you do she still jumps and jumps and jumps and once jump activated she gets stunned where she lands and it sucks cause then you waste all your abilities and yet get nothing so I was wondering cause maybe this was done on purpose and is not a bug but I think it is, Tristanna can jump after being stunned which kinda sucks...