What I did: Scrolled to top of screen, click on Yesterday (in my case)
What happened: See video there are two words and Agenda has decided to just action Show Project
What I expected: To be able to assign another date
Things that might be helpful to know (Agenda version, OS and model, etc):
MacBook Air 2020
Catalina 10.15.7
Agenda 11.1 (151) - Mac App Store