Maybe this has been already fixed, but symlinked mailboxes are not shown by

[@ dovecot]# doveadm mailbox list -u test | sort Archive Archive/2018 Archive/2019 Archive/2019old Archive/Archive Drafts INBOX INBOX/test1 INBOX/test2 INBOX/test3 Junk Sent test testing-folder-home testing-folder-home/another folder Trash

dovecot-2.2.36-3.el7.x86_64 CentOS Linux release 7.6.1810 (Core)