I had this issue before, and it jus sorta fixed itself, when i open BSM the versions of beatsaber that i have installed dont show up on the left side of bsm. I could download every version of the game, that show its installing, when its done however, it jus disappears with the rest. After it fixed itself i was able to select and see my versions i had currently installed. Got on it today to try and play some more, and the same issue is occuring, i downloaded 1.40.8 and i cant see it now, or any of the other versions. If theres any actual way to fix this that would be great!