[Mark Henry]

Factory recommended case sealant, but it looks like young Dietter was a little heavy on the application.

SI 5900 is a superior RTV, squeeze out doesn't swell from oil and when applied properly any squeeze out stays put. I even think the long strands from to much sealant may be by design, it doesn't break off in chunks small enough to get past the pump screen. You will have fun removing that RTV, it doesn't like to come off, even after soaking in diesel.
Torn down quite a few 996/997 engines and have seen the same, but it was never part of the issue.

RTV gets a bad rap because peeps only think of the permatex stuff, but Threebond, (yamabond) is RTV, so are many others.
Loctite SI 5900 is factory spec, LN recommends it, look at Raby's vids...that's what he's using.
I use it on 996/997 case halves, plus I rub it into (no excess) many paper gaskets I install. It's definitely not the same as the old permatex.