ZBrushCentral

zbrush 4.3 symmetry not working. bug?

Hello, I just upgraded to 4.3 at work (MAC).
I have imported some objs from maya as I always do, one by one and organised them in subtools.
I’m 100000% sure these meshes are perfectly symmetrical, and that in maya the transforms are all frozen, reset pivots, and so on, been doing this for a while so I’m pretty confident there is no issue with the maya export side of things.

However when in zbrush I try to use smart sym or any other symmetry tool, the symmetry doesnt work.
Smart resym finds almost 0% symmetry on a mesh that I just imported and that should be perfectly symmetrical.

odd!

I checked the zbrush pivots, reset them to the original location (even tho I never move them), still no luck.

I started a new fresh scene and loaded one obj, and this time the symmetry worked.
I really havn’t done anything to the original scene a part from organising the subtools, and in years of zbrush use on various versions I never seen this problem. Did I do something stupid, like activated some shortcut I don’t know about, or is this a bug with 4.3?

I just remade the scene from scratch in 4.2 and it all works fine as expected.