Case Activating Phone

My mother-in-law has an iPhone 7 with a Wallet case. Frequently when talking on the phone - when the case is closed - the phone will mute itself. Today, the phone rang while sitting on a table, and without anyone touching it the call was accepted and we could hear the person on the other end start speaking. When she picked up the phone the call was on hold and the phone was dialing another person

is it likely that the pressure off the wallet on the face of the phone is performing actions on the phone without her knowledge? it seems that there are several credit cards pressing up against the face of the phone, and it may be worth noting that several of the cards are RGID enabled. Also, the case has a magnetic clasp.

any thoughts?