Comment 4 for bug 1918410

Denying
  /proc/1095210/task/1095213/comm

prevents the task from introspecting (reading), and changing (write) the command text associated with the task. In this case it would appear one thread is attempting to change the comm of another thread in the process (this is generally allowed), see man 5 proc

Reading isn't considered a problem, writing is more interesting. A process may use it to provide more info, like this is a sandbox thread, renderer etc. But a compromised task could also use it to masquerade its comm as another task. It won't hide the task but could make it harder to kill or monitor if the user is looking for the default comm value.

Denying this is not directly related to lack of IPv4 (kernel wise it has no relation), but application behavior could be such that when it fails to access the comm field it handles the error poorly resulting in it failing to setup IPv4.

I would recommend a modification to the above rule, changing [0-9]* to @{pids}

  @{PROC}/@{pids}/task/[0-9]*/comm rw,

Does adding the above rule fix the IPv4 issue for you? From comment #3 I assume no, but maybe I am reading it wrong. Are there any other denials in your logs?

As for disabling AppArmor for dhclient? It is precisely the the type of service (network facing root service) I would not recommend disabling the apparmor profile for. Instead updating the profile is the way to go.