Normally, there is only air under pressure coming out of the weep hole.
There can be two causes for fluid coming out, turbo seal leaking, or raw water intrusion into aftercooler.
Usually the inside of the intake tract is covered with oily/carbon film, this is normal. Factory placed weep hole on there for a reason, so it will show you if oil (from turbo) or saltwater (raw water) has leaked past the aftercooler element and into the intake system. If there was no weep hole, engine would ingest and have to compress the fluids (oil or the salt water) and by the time you notice motor would be hydrolocked or rusted out from the inside.
This seems like first signs of saltwater intrusion. Salt water under pressure detonates and will clean out old residue from the surfaces it comes into contact with, in this case the normally oily intake manifold system. The leftover moisture will leak out the weep hole as brown/black colored mist. If you remove aftercooler, and find inside air passages to be spotless clean, you have salt water leak.
Is your oil level normal or are you using/burning oil? If you remove the aftercooler and find air passages to be covered in excess oil, and your motor is "losing" oil level, you have turbocharger oil seal leak.
Hope this helps.