I updated to 2020 Sp3 last night.  Now I am trying to add a very simple coincident mate between two surfaces.but the surfaces will not select.  I am at a loss. 

• I checked the System options>selection  and they look Ok.
• My selection filters are all off.
• I can box select the components, but not the faces I need.
• Components are resolved.
• I can mate the reference planes together with no issue.

What in the world is going on?

I am trying to add a coincident mate to the surfaces indicated in red.  The bottom side of the flat bar and the top surface of the tube.