Poly D sticky key sounds


Hi everyone! 
so just wanna say I really love the poly D! The tones that can come out of this beauty is insane!

The only problem I have is there's a couples of keys (A2,A#2,B2) that are making a weird sticky sound when i press them a bit harder, like a physical sticking plastic sound! So i thought oh maybe i got a bad unit so I ordered a second one, which to my dismay, does the same thing but just on different keys this time. 

it doesn't affect the sound in anyway but at a 1000$ CAD I would have liked to see a better quality control!

Im hesitating about my next move, do I send them back to amazon and hope that the third one is gonna be ok? Is it worth it or they all do that? 

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