This bug was fixed in the package update-notifier - 3.189
--------------- update-notifier (3.189) bionic; urgency=medium
* Do not notify-reboot-required on linux-image-extra removal (LP: #1458204)
-- Julian Andres Klode <email address hidden> Fri, 12 Jan 2018 09:51:27 +0100
This bug was fixed in the package update-notifier - 3.189
---------------
update-notifier (3.189) bionic; urgency=medium
* Do not notify- reboot- required on linux-image-extra removal (LP: #1458204)
-- Julian Andres Klode <email address hidden> Fri, 12 Jan 2018 09:51:27 +0100