There shouldn't really be oil in that pipe, in "sorting the problem" it is likely you are ensuring the oil makes it's way into the engine, I would be looking for where the oil is entering the intake system, you have cured the symptom not the problem IMO, it's good to replace the clip as it is likely you were losing boost pressure, but I would rather the oil was forced out of the hose than ingested. Try the engine breather pipe to see if that's where the oil is coming from, it's why some folk fit "catch cans" into the engine breather to separate the oil out.