Hey, the Tips and Tricks offers a possible solution to this.
Open up CrossOver and then hit "Programs" in your menu bar, click "Run Command" and a dialogue box will pop up.
Select your Guild Wars 2 bottle from the drop down and then in the command line hit Browse and direct it to your GW2.exe
The next step is crucial, before you hit run you need to go to the end of the command line and type in -image
It will look something like this |"/Users/Name/Desktop/Guild Wars 2/GW2.exe" -image| (The quotation marks are added when you use the browse menu and the | lines are what I added to show you the boundaries of the text it should show.)
Then hit save command to programs and then run the command (Either by hitting run or by clicking Programs in the menu bar and then selecting the command you just created).
This should force it to install any updates if there are any. However you shouldn't play the game using the -image command.
As a side note, this is an issue that was experienced in past betas and the problem was actually with faulty updates from Arenanet, so HOPEFULLY when they release newer updates closer to the beta you can update and it will work just fine :)