Radiator leaking from lower fitting

I have a 2002 hyundai santa fe v6.
I replaced the radiator about 2 years ago, and within the last 6 months, it has developed a leak.
The leak is coming from the bottom of the radiator, from the aluminum fitting shown in the picture.
I guess I don't really understand that fitting. Is it a power steering cooling loop?
Regardless, it is leaking coolant from that fitting. In the attached photo, you can see a drip of coolant.
When it starts leaking, I just snug up the fitting and it stops leaking for 2 or 3 weeks.
Then it comes back, sometimes in larger volumes than other times.
Has anyone else had similar issues?
Are the plastic threads in the radiator itself stripped? They feel good when I go to snug it up. I can put torque into it and it snugs up nice. It just seems to loosen up over time.
Could there be a crack in the plastic?
Trying to avoid draining the fluid and inspecting. I should probably just order a new one regardless, it must be cracked?

Any thoughts or advice would be greatly appreciated.