Take it apart again. Put it back together. This time flip the bushing that goes in the blade. Only tighten all the screws about 50%.
This has happened to me in the past and I found that for some reason the CBL needed to be able to put itself where it needed to be. I opened and closed the knife slowly a few times with the screws loosened and then I tightened the pivot almost all the way down. Then I tested to see if the play was gone. It wasn't so I sort of moved the handles up and down and sorta just played with them and then I heard the CBL sort of "click" into wherever it needed to be. After that I tightened everything down and all was good.
When I say "moved the handles up and down" what I mean is this: If you hold the knife with the back of the handle facing you and the blade tip facing away from you with the edge down and the knife open you will be able to hold a handle with each hand. You will be looking down on the spine of the knife. Like this you can grab each handle scale/liner and tweak them up and down and back and forth a little. Do it with the blade open and also with the blade closed and see if you can get a "click" and then see if the play goes away.
Let us know.
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"Knowledge without milage equals bull***t." -- Henry Rollins