Samsung 5 Ultra type jumping

I bought a Samsung Series 5 Ultra several months ago and it's driving me crazy because, as I'm typing, something happens and the letters jump to an earlier point in my text. This happens whether I'm typing an email (aol or gmail), or using word processing software or doing really anything that requires typing.

I think it may happen when my hand brushes the keypad but I can't seem to type without that happening occasionally.

Is there any fix for this?

Thanks very much.