Locking issues and contentions possibly caused by materialized view

We are using Oracle 19.7 on Linux.

I'm suspecting a materialized view to be the cause of massive locking and contention issues.

We have added a materialized view a couple of months ago, to address performance problems by some expensive queries.

While this works fine most of the time, occasionally we see some contentions and locking issues. End users are reporting long response times by the application, and sometimes timeouts.

I'm not sure the issues are all caused by the materialized view, since there have also been other functional changes to the application.

But the logs show a lot of erros related to the materialized view and materialized view Log