New to me keg issue

So I was filling kegs the other day, and as usual, hooked up the CO2 and sprayed soapy water over the lid and around the posts. All looked normal, no discernible leaks. I left the CO2 on for a while while I did other things in the brewery. Then I noticed the keg was leaking from the pressure relief valve. It took a while before I noticed, just little bubbles around the valve. Usually, I just spray, check the lid and the posts, then wipe off the soapy water. Fortunately, I didn't do that as quickly this time. It turns out to be a pretty easy fix.

The leak is from the small holes next to the lid.

A 1/4" socket extension fits the square hole in the relief valve well enough. There is some slop, but not enough to cause a problem.

Lubed the o-ring and all is well.