Having the hardest time selecting masks and mask components.... CC2017

So I have a mask on a solid layer, creating a frame with the mask inverted. The comp layer underneath is a simple video clip. Nothing complicated, right?

I can't for the life of me select the mask shape in the composition panel. If I click on top of where the mask SHOULD be, using the SELECTION TOOL, nothing happens. If I double click, I open a new panel with the mask showing. What I NEED is to be able to select the damn mask shape and move it's control points to edit the shape a bit. Nothing complicated, right?????

This behavior happens only when I first open the comp. I cannot select any mask item with my selection tool. BUT, if I switch to the pen tool, and click on the mask, I create a new point on a NEW mask item, however now my original mask is highlighted, the solid layer frame shows up in my comp viewer, and NOW I can select the mask even with the selection tool. I cannot select my simple mask prior to creating another mask item with the pen tool. It's as if it doesn't know a mask is here. Even if I select the mask in the layer tab, it does NOT highlight in the comp view. I first have to get it to "activate" (for lack of better term) by using the pen tool.

Once I get it to work again, it's fine. However, this behavior seems buggy and I wanted to bring it up. I can't reproduce this by closing and re-opening After Effects. Perhaps it comes from duplicating the comp first... I'll report some more when I find what is causing this.