Calendar need an account to work (and try to connect to google by default)

Calendar can't work without an account

Summary

when I click on "Calendar", everytime, a pop up suggest me to connect to Micro-G, even if I select IGNORE

Steps to reproduce

On a fresh-installed e os on Nexus 5, don't connect to any services (no google account, no /e/ account, nothing else), open "Calendar", you will be prompted to signin in on MicroG services. Ignore it, you can access the calendar, come back to main page on your phone, try again > same prompt, restart phone, try again > same prompt

What is the current behavior?

prompt to sign is MicroG service

What is the expected correct behavior?

shouldn't ask this at all or, if I clic ignore, it shouldn't ask me anymore

Relevant logs and/or screenshots