Trying to get ":" key in Gnus summary to add/edit senders in BBDB (again)

Platform:
 GNU Emacs 30.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.49, cairo version 1.18.4) of 2025-07-18, modified by Debian
 Gnus v5.13
 BBDB 20231122.1326 from ELPA

Need help getting BBDB in Gnus working again.

I have stripped away all prior configuration and the only BBDB-related
configuration in my ~/.emacs is now this:

(when (locate-library "bbdb")
  (require 'bbdb)
  (bbdb-initialize 'gnus 'message))

bbdb seems to have initialized something because 'C-h b' in the Gnus
summary buffer now list the following two bbdb-related key bindings:

:		bbdb-mua-display-sender
;		bbdb-mua-edit-field-sender

However, pressing ":" on a message in the summary buffer does nothing.

What I expected ":" to do was to open the record for the sender of the
message I was on in the Gnus summary buffer, or to add a record for that
sender if the sender wasn't already present in the BBDB database.

The ESC+TAB I use to insert receipients in messages, work with the above
configuration and offers to expand addresses for people in the BBDB
database. 

All ideas or debugging tips are welcome!

Thanks!