This afternoon whilst working in my back yard, my iPhone 11 made several random calls all on its own. The phone was sitting on top of a wheelie bin approx 10 metres away from where I was working. I didn't have any music playing nor did I speak during this time, so it could not have mistaken anything for "Hey Siri". It only dialled people from my Favourites list.

I have done a Google search and it only seems to be people having this issue when it is in the pocket, which may or may not be related to my issue. 

Anybody else had this problem?