Update notification for alpha channel takes user to non-alpha upgrade page

It seems like if a user is on the alpha channel, the upgrade page link, contained in the top right hand pop up window, that appears upon auto-update failure, should be for the alpha upgrade page.

(This has come up due to auto-update failing on many occasions on different versions, requiring manual replace instead. Have wondered whether this could be due to location of app in slightly non-standard path, or some permissions setting in the Application Support folder, but otherwise don't know why it never works any more.)