It seems that the Blueprint function Break Structure is erhh… broken.
If you take a vector, apply Break Structure and use one of its outputs, it defaults to the first available one when closing and reopening Rocket.
I’ll let the pics speak for themselves:
Temporary work-around ( if you only use 1 of the outputs ) is to hide the pins for the other outputs.
I was testing out this issue and it would appear that it was known. You can expect it to be fixed in the next release. If it isn’t let us know and I’ll open up the issue again.