Just to recap.
It is 1.8.7 CMS docker on linux, correct?
I assume from your post it was upgraded several times now, correct?
I wonder if those issues are related to browser cache, did you try to clear it / use different browser?
Failing that, could you access the database in the web container and run
SELECT * from module;
or
SELECT * from module WHERE `Module` = 'notificationview';
and see if notificationview module is present in the database?
Accessing mysql on docker is explained here How can I run a SQL command when using a Docker Install?
it’s not complicated.