Hi Thomas

If you want to get xref's layers on/off settings synchronized in your current drawing, you need this command 'VISRETAINMODE' , and change the value from 0 to 1( or from 0 to 2047). 

But you can't see this command before version 2019. As a recommendation, please update your AutoCAD for Mac to the latest version like AutoCAD 2023  and it can help solve your problem.

See these two pages for more details.

https://help.autodesk.com/view/ACDMAC/2023/ENU/?guid=GUID-32CFDDB7-E6F8-4BEF-9538-65862F87092D

https://help.autodesk.com/view/ACDMAC/2018/ENU/?caas=caas/sfdcarticles/sfdcarticles/Modified-xref-la...

Quinn Zhang

AutoCAD for Mac team.