Apple iCloud Mailbox Icon Disappears in Monterey 12.3.1

I've had a problem with the iCloud icon under All Inboxes disappearing on Apple Mail when Mail checks for Mail. The top graphic shows the Inbox array when I first boot up Mail. The bottom graphic shows what happens after the first time Apple Mail checks for mail. Note that iCloud inbox name is replaced with Inbox.

I am still getting mail adequately, so no complaint in that regard.

[Image Edited by Moderator to Remove Personal Information]