Antifreeze leak on header flange

Well... Got home a little early so I took a look at it. Headers have studs on all but one place on header flange. Second from back is a bolt. Checked them and everything is tight.

Could it still be leaking out of there if they are tight? I felt around under there and it definitely feels like that is where it is coming from. It was wet under flange at the back bolt.
sure it can leak if there was no sealer on the threads and/or the threads are damaged.