Keyboard problem - Hi9+ 2019

Hello everyone, I’m having a little problem with my Hi9+ keyboard.
Sometimes it happens that I type something like “Hello” but “Heello” gets on the screen.
Basically it doubles random letters! I’m also quite quick at typing, so it’s not that I hold the keys down too mutch time.
I have no idea why does it happen, but it does happen and it’s not a nice thing.
Thanks everyone!