So I just bought a used 2014 Evoque, drove it awhile no issues, then I filled up with gas and when I pulled into the garage gas was leaking out from under the car. I took out the rear seat and removed the cover plate over the fuel pump and gas was leaking out of the white nipple shown in the picture.
It appears that the top of the nipple somehow was worn a little which left a tiny hole for gas to leak out of. When I ran my thumb over it, gas came out faster, shooting out maybe 1/2”. Note this is all when the car and ignition are turned off. After the car is off gas continued to leak for several hours.

Update - I bought a 1/4” i.d. fuel line, cut it to about 3” long, capped one end of it with a brass fitting and thread-on cap (using Teflon tape), and put the other end over the nipple securing it with spring hose clamps. Seems to have taken care of the leak.
Wondering why that nipple fitting is even there? I couldn’t find any hose that should have gone on it, and it seems to run fine with it sealed up.
Anyone have any comments or insight on this?

 

The nipple having the raised ring at the bottom, it almost looks like a fitting was attached. ???

 

That's what I thought - but I couldn't find any hose in the area that would have hooked up to it. And now that it's plugged, the car seems to run fine and gas doesn't leak.

 

I would say, job done.