Unusual rust issue???? (Dsg)

[Polo6n1600i]

So my B6 V6 has just gone in for its 118k service, inspection & mot.... Oil, filter changed, brakes checked, brake fluid renewed....

But while it was up on the ramps - a damp section under the gearbox was noted. Right on the front face of the DSG sump/plate.
It's gone porous & letting dsg fluid leak out!!!

Dsg service was previously done at 88k.... So looks like I'm also doing a dsg service & a new sump!!

Anyone else had this???