The albums are not available in your country anymore probably . That’s usually due to expired contracts and copyrights stuff in your country . The catalogue in every country is very dynamic and can be changed all the time . 

You can however ask Deezer to bring it back by using the following link 

Albums are there, but you have to know how to look for them, they are not visible in the ordinary discography. This is not just the case with The Beach Boys but with a lot of artists

If I’m correct, this can be fixed.

@Jaime.Deezer are you able to fix this or could you send in a request?

@Slick2007 could you please report it as a problem in the app, from a PC/Mac, and one a member of the music team will look into it.
Thanks and apologies for the inconvenience