I tried to replicate your issue. I created a status called "Deskphone and Softphone" and added both of those destinations to the status. I called my main number and both deskphone and softphone rang.
So this begs the question: you don't mention that this ever worked for you before. Has it? If it has, then something has changed, we just don't know what. If it has not, then there might be additional setup required on the PBX or the UC Server.
While I am not an expert, I would check to make sure you have softphone licensing, Dynamic Data Extension licensing and that your user information in the pbx (we have a 5000) also has the softphone information added to it.
I have found that to get this stuff to work requires setup in both the 5000 and the MAS and the UCA end point. It's not like you can put it in in just one place and it works. You have to check A, B and C to get it all to work.
I think that's why I'm the only person who uses it?
Hope this helps.
Adam in DC