This looks like auto-connect. Visio suggests you to glue the connector to that thing, whatever it is. You can:
- Disable auto-connect globally (google "how do I disable auto-connect in Visio")
- Figure out, what that thing is (it must be some shape anyways? - you could try drawing explorer) and either delete it or disable auto-connect for it.
- Stop misusing Visio for drawing schematics

Also, attaching the broken Visio source file could help - people probably will be able to figure out the cause more precisely.