Precondition:
Jenkins 2.277.4
Ubuntu 20.04.2 LTS
openjdk version "11.0.11" 2021-04-20
Problem: I have a Freestyle Job For First time all the done changes are saved (At this moment 'Save' and 'Apply' buttons are at the mid bottom of the page) Next time If I come to do some more changes and try to save, it doesn't work AND no error at all neither in browser 'console' or 'network' (At this moment 'Save' and 'Apply' buttons are at the left bottom of the page)
This issue is similar to this issue raised in Jenkins jira https://issues.jenkins.io/browse/JENKINS-65142