2.8 TFT rewriting characters "flashes"?

I am a little gobsmacked. You appear to have an SPI ILI9341 display from "Adafruit_ILI9341.h".
But have a resistive Touchscreen. Perhaps it is a Seeed Studio display which has got level-shifters.

Your sensorPin = 53 implies a Mega2560.

I suggest that you look at Bodmer's libraries. I know he has a TFT_ILI9341 library.

I would use the GFX_Button class whenever possible.

Oh, and as a handy tip: press ctrl-T to format your code. It makes the world a better place !!

David.