Drat. I gutted the original BP with the problem and my tiny schematic does not duplicate the error. I had been able to determine that the rotator did not disappear if I removed the pipe.. but the error reoccurred if I put the pipe back (I was trying to make sure I had not linked it in some bizarre way).

Will try and find the original BP and strip it down to the bare error essentials.

Stripped down problem from the original.

I stripped everything from the original problem ship, and redid all the logic, even replaced most blocks in the problem area. It MAY be the file itself is corrupted in some weird way but it does work.. without the pipes. Maybe other blocks will have different effects (should try a console to see if it's non-cubic blocks only).

i think the BP is broken.

that logic connects to thin air ...and the air claims to be a pipe.
broken meta data.
there are still known bugs with place and replace of formerly connected block locations that can cause ghost connections and mostlikely problems like that.

It's a new BP (only 2 update version old) and I don't do Search & Replace that early in BPs. Those Rotators where probably within the 1st 100 blocks (no logic at that point). I did however create the docking from the 'creating docking' in advanced build mode.

If I get another like this I'll add information. For now it could be a bad BP.. so strange it works perfectly UNTIL you add the pipes. Perhaps check if the

erm, you can change rails, rotators and things like that to pipes and consoles, like you would change the other rail items