Seeing the same for 20.04:
[ 171.828819] audit: type=1400 audit(1598467536.663:28): apparmor="DENIED" operation="open" profile="/{,usr/}sbin/dhclient" name="/proc/1060/task/1063/comm" pid=1060 comm="dhclient" requested_mask="wr" denied_mask="wr" fsuid=0 ouid=0
Seeing the same for 20.04:
[ 171.828819] audit: type=1400 audit(159846753 6.663:28) : apparmor="DENIED" operation="open" profile= "/{,usr/ }sbin/dhclient" name="/ proc/1060/ task/1063/ comm" pid=1060 comm="dhclient" requested_mask="wr" denied_mask="wr" fsuid=0 ouid=0