Fabia II oil leak

Hello,

Two months ago my fabia start to leak engine oil after doing the 60000 km service.

Skoda guys claimed that the oil pan is the problem, then we changed it.

The leakage doesn't stop, so I went to a mechanic.

He found that there was a Two loosen screws (in the photo), he said that was the reason.

the leakage has stopped now, but the question is:

Should it be an engine oil behind this plastic cover?

if no, so what is the problem?

My car is 2009 fabia II, 1.4 petrol engine.