Touch screen is acting crazy after a year

I replaced the screen on my daughter’s iPhone 6s+ (with an iFixit screen) just over a year ago. A few days ago, it started to spaz - acting like it was being touched and swiped when nothing was touching it. I removed the screen protector, took it out of its case, and even cycled the power and did hard resets. Nothing would stop the behavior.

Is it possible that the screen has gone bad (just after the warranty expired, of course)? Is it worth replacing the screen again, or is it possible that something else is wrong. I don’t know if this model is prone to “touch disease” or if some other component might be causing this problem - or is it just the screen?