A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
After a good deal of Google research, I found that we are not the only ones with this issue and the only solution available is a work-around.
If you find that you are not seeing all tags in a notebook, close the notebook and reopen it. The Find Tags function will not work properly. This worked for me in every Notebook that I was previously having the issue in.
Not the best work-around, but it makes the tagging function work as intended.
I hope this helps.