!rant
Any tips on fixing a mechanical kb that registers certain keystrokes twice or even more?

Sure. You can go to your local tech store and buy a normal keyboard.

On mine a firmware update helped

This happened to me after I'd spilled water on my kb. I've tried decontructing, wiping everything a putting it together....three times! I didn't break it but didn't fix it either. I ended up refunding it and people at the store didn't notice a thing about me opening the keyboard (Which I was't supposed to do)....not even the safety sticker being torn off. :D

Thanks! I'll give those a try