The magnetic case does affect the display of the phone

I just found out yesterday what the cause of my screen being jittery as well as when I was typing within a text message it would not type the keys i was pressing on. I have a Evutec magnetic carbon case that i bought from Target not too long ago, and my phone started acting up days after, I did not pay attention thinking that a simple reset will do the trick. However, after the reset it started doing it again. I did a restore several days after, and a day later back again to the same thing. Yesterday, it started acting up even more, so I literally took the case off, and within a second everything was fine, just like nothing happened. Looking at some of the apple official responses, it seems that they do not recommend having magnetic cases on the Iphone, however when you look it up on Google all of the case makers mention that it does not affect the phone....hmmmmm.....I wonder how many people out there that do have cases and experienced the same things I have been know the real reason why. I was about to go to ATT and have my phone replaced since I thought that it was on its last leg. Ohh BTW I have an Iphone 7.