Funky looking Ignition coil.

I bought a 2017 TRD Offroad with a 2GR around this time last year, it had 157k miles on it when I bought it and I'm now up to 165k. I'm not 100% on the maintenance history so I've been fixing little things like changing every fluid, replacing the leaking rear shocks, changing all the filters, and fixing the broken stuff.
I just jumped into replacing the spark plugs and I pulled all the coils and 5 out of 6 were in good condition but the coil in cylinder #3 was covered in a dry, brown crust from top to bottom and when I started taking the plug out it didn't break loose like the other ones it just started spinning but it was coming out hard. The bottom of the threads had a little bit of a brown sticky substance on it too but the tip looked ok.
I was just wondering if the seal for the tube was gone leaking some oil on it and wondered if I should get it fixed right away or not. I'm gonna put a new coil in it and check it in the spring as long as I don't get any major misfires.

 

Sounds like the plug wasn't tightened down properly and it was leaking around it.