The JOIN SERVER option doesn't appear only BUY

On the EA App (PC), when I try to locate specific servers, they appear in the list, but when I select the server, the JOIN option appears instead of the BUY option. I purchased the BF6 STANDARD version. Is this expected, or is this actually a bug? If it's expected, does that mean the STANDARD version can't join dedicated servers? If I use the MULTIPLAYER option, it locates the game based on its type, and it works normally.

COMPRAR = BUY