For anyone struggling with this - the problem was with rules precedence inside /etc/sudoers.
By default if there are multiple entries for a user inside of the /etc/sudoers file, sudo uses the last rule that applies
The change to jenkins user was being overridden because of the rule’s position in /etc/sudoers :
WRONG
It is wrong because jenkins user is already a member of sudo group, and thus the line jenkins ALL=(ALL) NOPASSWD: ALL will be overriden by the line
sudo ALL=(ALL:ALL) ALL
CORRECT