Question Simultaneous touches on horizontal axis being ignored on LG and Samsung devices only

I have a music game out on iOS and Android. On iOS and many Android devices, the game works great. However, on LG and Samsung devices, I am having a lot of users complain that simultaneous touches of two notes at once only results in one touch being recognized. This is a very consistent complaint across these platforms. They say the touches must be hit slightly off beat from each other to register.

Is this a hardware issue? Is there some form of gesturing I can disable? My game is essentially unplayable if two touches on the same horizontal axes cannot be detected simultaneously.