I have the same Problem
for few month i have changed the original Intercooler Hose,because i want blue silicon Hose.
Every Enginecleaning i wondering, if this Oilfilm where normal or my pipe had a leak.
on this Way, i checked if the Intercooler-Hose fit perfectly and I checked the Hose clamp.
Now, could you say me, if this is normal or not ?