Hi Junito! To unlock Havoc, it must be an Auric or Non-Auric Maelstrom mission and it sounds like you’ve done both! Could you share the URL to your Steam profile with us, please?
You can only unlock Havoc after reaching character level 30.
So… it wont unlock by doing a maelstrom before level 30 and then reaching level 30, you will still need to do a maelstrom again after reaching level 30.
You need to do this with each character, even if they are all at level 30. Doing it with one doesnt count for the other characters.