boundary condition at split line

Second question today:

I've a sheet metal assembly framework with three feet.   One of the feet has split surfaces, as it's part of a larger assembly model where there's an offset load, and one side will be in compression, and one side will lift off.

I was running the framework model by itself to check it, and fixed the feet.  I noticed that if I didn't fix all of the split surfaces on the one foot, the analysis ignores the fixity completely.   As in my full assembly model one side will be bonded and one side no-penetration, this concerns me.

I also noticed that it ignored bonded contact surfaces, but not bonded component contacts.

Can anyone comment on this behavior?   I tried searching for boundary conditions at split lines, but didn't find anything.

thanks!

SolidworksSimulation