This is something simple I've been doing for years and am having a problem with it for the first time, perhaps I accidently toggled something on I am unaware of.
I have a simple cross section drawn in a World UCS view.
I switch to a 3D view, rotate my UCS so as to put the X,Y plane in one of the Z directions.
I then attempt to rotate my section into the above Z direction (obviously having chosen the one appropriate to the orientation of the section).
As soon as I select my objects and enter, the UCS automatically reverts back to World, allowing me to only rotate my section in plan.
As soon as I abort the command, the UCS automatically reverts back to the one I mention setting up above.
Any applicable suggestions would be greatly appreciated.