Hi,
The simple answer might be to reassign "Get material from object" to "Pick material from object" instead, using the Hotkey editor. This will add one more click, but it will most likely prevent this occurance from happening again. This answer is based purely on not caring why or how 3DSMax is doing this, but rather a quick workaround instead.
If it is an unresolved bug in 3DSMax, being on the third hotfix for 2023, things are not looking good for a fix from the Max side. Not specifically blaming Max here, but it could be countless things causing this. If everything on your side is updated, then the blame is removed from the user.
Regards,
Darawork
AutoDesk User
Windows 10/11, 3DS Max 2022/24, Revit 2022, AutoCad 2024, Dell Precision 5810/20, ASUS DIY, nVidia Quadro P5000/RTX 5000/GTX760