This is just a minor inconvenience at worst but anyway. Repro: 1) Start building with GC rotating anchor ((without build beam). 2) Build a couple GC long girders upwards (as needed for ground clearance) 3) Add GC basic block on top 4) Build in any sideways direction with GC long girders until the tech would go out of building area and is re-centered. 5) Observe how the tech now rotates around the point where the anchor was, rather than where it now is. 6) Optional: wonder why anyone would want to build such a thing. Trivial fix: enter and exit build beam. This will update the rotation pivot to the anchor.