Assistance with Visio - Org Chart connections breaking and rearranging themselves

Hopefully this is the right place - I saw the Visio subreddit but it looked pretty dead. I maintain the org chart for my company and it was made entirely in Visio, but I inherited the file from someone else and I have no idea what its been through. I'm going to explain this as best I can - I have a page where there is a Senior Leader at the top, then a connection going down to a Manager, then under them is three Teams with connections to the Manager. The three lines are connected to the bottom-middle of the Manager box. If I do ANYTHING to the Manager's box, including resizing it, the line on the right repositions itself to the middle-right of the Manager's box. If I try to re-connect that line back to the bottom-middle of the Manager's box, the line from the Manager up to the Senior Leader deletes itself. If I try to draw a new line from the Manager to the Senior Leader, the line from the Team to the Manager deletes itself and I'm back to square 1. It's absolutely maddening! I had to learn Visio as I went - is there a setting somewhere that I'm unaware of causing this weirdness?