OM642 Valve Cover / Cylinder Head Cover Bolt Leak

[WaarrEagle]

2009 E320 Bluetec. I have had seepage on my passenger side valve cover (or as Mercedes calls it, the cylinder head cover). I finally got in there to clean it off and there is a moderate oil seep from one of the valve cover bolts. Essentially the same issue as posted here but from the next bolt over: https://mbworld.org/forums/diesel-forum/762034-om642-mystery-oil-leak-near-fuel-injectors.html

From looking at WIS, this bolt penetrates the head inside the sealant bead, so what is supposed to stop it from leaking? I tried tightening a bit and it did not help. I did find one forum post implying certain bolts need sealant but nothing in WIS. Should I apply sealant to the bolt as a quick fix or do I need to prep to remove the whole cover?

The bolt in question is highlighted in the diagrams below.

[engatwork]

Applying sealant to the bolt is the way this is typically taken care of.