When I installed the spar I applied thin CA while applying a down pressure on the spar to make sure it went all the way down, so it did not come loose and rise after applying the CA. I thnk right now it is all the way down as it can be. The only explantion is that some of the shear webs need more sanding to make them flush with the notch, although I am almost certain I did that before installing the spar.