Not sure if this has been discussed, how will this affect VoIP users? I'm guessing people with 2deg VoIP landlines will be ok, but one of the reasons I've stuck with 2deg is because of the public IP for 2talk to work properly.
Not a VoIP expert at all, however, I imagine it works like most client/server applications.
Its likely your VoIP client (you/your PC) connects through to your provider (the server) to log in etc. It will then hold a TCP session open to allow calls to be made back to you. Whenever that session is dropped (cause the Internet sometimes has problems....or you change networks - eg cell phone moving around cell sites) the client will re-establish a connection.
CGNAT should recognise that session and keep it open too - it would have to or dozens of applications would stop under it!
Since its all out from your side, your IP address is pretty meaningless! Certainly your provider has no way to know what your IP address is "today" at any point in time.
TLDR: It should be of absolutely no impact to you.