As a workaround...
If you're aware you haven't flown in a while, create a folder in XPlane/Resources/plugins/ called disabled.
Drag terramax into the disabled folder.
Start X-Plane, open the Gizmo / X-A licensing window, update your license.
Quit X-Plane.
Drag terrmax out of the disabled folder.
Start X-Plane.
I'm aware it's not optimal. I'm aware that you may still get caught off guard when all you want to do is fly.
I'm just offering a constructive work around.
As the author of Gizmo I am unable to change how terramax operates when it's not licensed.
I might be able to tweak Gizmo so that it allows terramax to believe its licensed for the first few minutes of sim operation but I will have to discuss this further with other stakeholder and investigate the technical challenge in doing so.
I will add it to the bug/features list and review it again when other higher priority items have been worked through.