On receiving a networking error, Evolution 3.8.x removes any folders it was in the process of checking. This means that folder caches are cleared and search folder configurations are edited.

mbarnes believes the commit which caused the problem is:
https://git.gnome.org/browse/evolution-data-server/commit/?id=dacf16165d22e08c1f758144ec5e9f4d8c6da0d0

To reproduce:

 * Configure an IMAP account
 * Add a search folder with the INBOX to that IMAP account in the search folder
 * Cause a network error (suspend for 10 minutes and resume, disconnect the network cable, etc)
 * Reconnect the network or resume the laptop

What should happen:

 * Evolution should detect the network error and attempt to reconnect without changing any configuration

What actually happens:

 * Evolution receives a network error, removes the open folders from the display, clears the caches, and removes the folders from the search folder
 * Later, the folders may reappear in the UI, but the configuration will not be restored, and the caches will need to be rebuilt.