I feel bad for you folks who have to key in a MP number. One of my favorite parts of The MVPG line is that they immediately know who I am, my status, and upcoming flights after I verbally confirm my name.
UA 1K line doesn’t do this and have always thought, “wow, here’s something AS tech is actually doing better than the competition.”
If it isn’t working for you, I would talk to CS about what the cause could be and HUCA if necessary. It’s a valuable time-saving feature when everyone is trying to get on a new flight, post-cancellation.