It’s probably because the ID is not recognized by Org-ID.
I could reproduce your issue and could also fix it.
Try this to see if you get a marker returned.
(org-id-goto "210504_080047")
;;; EDIT sorry, I meant this function for marker
(org-id-find "210504_080047")
;;; org-id-goto takes you to the buffer -- it might give the same insight but not sure ;)
If not, you would need to update the hashtable and locations file:
(org-id-update-id-locations (list (buffer-file-name (current-buffer))))
We discussed a solution to update Org-ID for externally created files or manual ID elsewhere. It does not seem to work within Org-roam any longer. I now have the following to ensure org-id-locations-file is in sync with Org-roam cache for my IDs.
(advice-add #'org-roam-db-insert-file :after
#'my/org-id-update-location-at-org-roam-db-insert-file))
(defun my/org-id-update-location-at-org-roam-db-insert-file ()
"Update `org-id-locations-file' and hash table.
It's meant to be used with `advice-add' :after
`org-roam-db-insert-file'. We can assume that this function is
run wihtin a buffer visiting a file being inserted, as
insert-file is run within `org-roam-with-file' macro."
(when-let ((id (org-entry-get 1 "id")))
(org-id-add-location id (buffer-file-name))))