If you have never seen this issue before and are an electrical discipline user, you are extremely lucky. When adding wiring to electrical or lighting fixtures built in a face-hosted template, sometimes wires jump around in a frenzy every time a fixture is moved. This is obviously unacceptable, but luckily there is a fix. Let’s break it all down.
You place fixtures, add wiring and all is well. Then you make a change and move some fixtures (because that’s what designers want), and the wire ends are sent off flying all over the place. You think about hurting someone, but keep your cool instead.
So what causes this? Thanks to a tip from Autodesk Support and further digging, it turns out that there is a potential bug in the face-based Generic Model template, which is probably the one used for your families. When the internal origin of the family is in a different location than the ref. planes that define the family origin, you see the above behavior, where wire connectors jump to the “projected” location of the electrical connector.
Below we can see two instances of the Lighting Fixture above with a wire added between them. The wire end connections match up with those of the fixture, but the wire end graphics are goofy.
When the fixture is moved, the wire connects to this “projected” connector location and thus appears to disconnect and jump around.
To fix the problem, make sure the origin defined by the intersection of two ref. planes is at the exact same location as the family’s internal origin. This way the true connector location is used to connect the wire end instead. The positioning of family geometry in relation to the origin is not important for this to work properly. Here is the proof: