Do not silently change the “Sent” Mail forder from IMAP-remote to “On this computer/Sent”
My default folder for storing sent emails is IMAP-remote/Sent. From time to time Evolution changes it to “On this compiter/Sent”. I have observed also for Address books, that the default CardDAV-based was changed to the local address book (when adding new contacts). But I do not know how to trigger this and it happens very seldom.