I just checked again, and I found something strange -
I placed a default cube and rotated it in the red/left/negative y axis. - Then testing this bug by holding SHIFT while moving an axis so the camera comes along for the ride, I don’t see any problems (I must have just only checked this axis previously), BUT - if any other axis is rotated, I still see the bug.
I’m not sure what you mean by ISM editor? (Instanced Static Mesh Editor? - You’re talking about moving around objects inside of a Blueprint?)