Can't add user to group without a restart?

The command groups is not showing you as a member of wireshark and you're unable to use wireshark properly unprivileged. Chances are something has not worked with the adduser wrapper script.

What works for me when enabling new users to use wireshark is the following.

$ sudo usermod -aG wireshark $USER

Then log the user out and back in. You should now be able to use wireshark as a non root user.

It starter to show the appropriate groups only after a system restart. The logout - login wasn't enough.

Don't know what to make of it.