"Comments From Emails" Mail Handler Changed Its Handler Back To "Cloud Mail Handler"
When a user changes the settings of the Comments from emails mail handler, it reverts back to 'Cloud Mail Handler' after some time.
This happens because the Comments from emails mail handler is set by default on the Atlassian Cloud platform. Therefore, in every update for Atlassian Cloud, it will revert back to the original setup or it will be visible again if it has been deleted.
The user should not re-configure nor delete the Comments from emails handler because it is the Atlassian Cloud's default mail handler.
A handler other than the 'Cloud Mail Handler' can be created keeping the original unchanged. Note that the standard way to use the mail handlers is to create one per project.
For more information on setting up a mail handler, refer to Creating Issues and Comments from Email.