What I did: I tried to use the Features. Selected them, inserted something an then tried to enter them.
What happened: The Surrounding (blue-green // orange) opend up, I could enter the text, and when entering the surrounding disappeared leaving only the text…
What I expected: to have an nicely layouted Tag or Person - Sticker in my Note
Things that might be helpful to know (Agenda version, OS and model, etc):
Using a 2018 iPad Pro 11”, with the current Agenda version on iOS 12