Namechanged in case colleagues are lurking 
I’m a nurse in a clinic, we all have our own slots on the list so we know who is responsible for seeing each patient, but we all help each other out if we’re running behind, offer to take each other’s patients if we already know the patient from previous visits, etc. The nature of our clinic has a high non-attendance rate, so sometimes there are lulls in the day but there is always something else to do!
One of my colleagues has a habit of ambushing my patients at the door and calling them in before they have checked in via reception and been flagged as arrived, and the first I see that my patient is in the building is either them walking into my colleague’s room, or seeing my colleague’s name flag up next to the patient’s name on the list. If they haven’t got them at the door, sometimes they will take them from the waiting room after they’ve checked in, but not flag that they’ve ‘started’ them, so I’ll go into the waiting room and call the patient’s name several times, and another patient will tell me that they’ve already been called in, making me look a bit daft. This is all usually several minutes before the patient’s actual appointment time, so it’s not as if I’m running late and my colleague is trying to help me catch up.
Today, I had a student nurse with me and my colleague took FOUR of our patients, so four potential learning opportunities were missed and it must have been quite frustrating for my poor student, not to mention embarrassing for me as a mentor!
The most annoying part is that after the patient has left, my colleague will come and say “saw your 4pm for you” and look at me expectantly, waiting for me to thank them. It drives me absolutely bananas, nobody likes being bored when their own patients don’t turn up, but there are other things to do instead of poaching a colleague’s patients, surely! I’ve no idea if they do it to other staff members as I’ve not spoken to anyone else about it as don’t want to seem ungrateful or petty. No doubt my colleague would say that they are just trying to help, and they probably genuinely think they are being helpful but I can’t bear it!
AIBU or would this drive anyone else up the wall?!