I spent some hours on the phone with Apple yesterday and tried a number of things.
One thing that helped a bit was logging out of my account in Music program on the MacBookPro and then logging back in. It takes a while but a few less songs were in waiting state after that.
I did this multiple times yesterday and reduces the amount of waiting but it was still bad.
Today (this evening) I did that one more time and this time it finally came up and there are no waiting tracks any more.
Whatever they did on the server has finally cleared or all of those log-out and log-in operations finally cleared whatever was messed up on the server. I will have to encode some new CDs (I have still a few to do) to see what happens when I add them.
Hopefully this is fully resolved now.
PS - the phone call with Apple support ended up with them trying to claim I needed to re-install MacOS on my machine. I refused to do that since (a) I could tell that the problem was not local, especially with so many others having the problem too and (b) that is the most lame solution to a problem - restart and try doing the same thing again...
With the current MacOS, the OS bits are relatively secure - they are securely hashed and are protected from mutation. If they are changed and don't match the hash, you will be notified.
It is sad to see Apple falling back to such an lame process without even spending time looking into their server logs or working with me to track the transactions that seem to fail.