Teemo passive shenanigans....really needs changing.

So im laning against a teemo as pantheon. and my Ashe fires her ult. Big ice arrow comes in for the super long ston on the teemo so i q and w onto his face and POOF he goes invis due to his passive stopping me from landing the basic attack and promptly kills me once he gets out of the stun with his attack speed buff.... i dont know if thats a bug or not...but Teemo REALLY dosnt need to be going invisible WHILE stunned and taking damage....it feels seriously flawed that it even happened... i mean honestly for lack of better words....thats just stupid... a stun stops pretty much everything else in the entire game...so why not that