Rather an aggressive reply again Nubian, sadly all too common on social media nowadays.
I don't have my AS 350 notes to hand but ISTR there is a centrifugal filter in the scavenge side of the oil system that separates the returning oil and only passes excess vapour to the exhaust via a pipe which vents into the exhaust stream and not onto the exhaust itself - I find it unlikely that a glob of neat oil could find its way back through that system to the exhaust.
I'm quite content what an oil leak on a hot engine looks like - are you sure that LA video isn't a hyd leak or a fire?
As to your question - there is powder in the bags when packed - Rotorbees video clearly shows that. Is there enough to create such a big cloud? Maybe not but if excess was put in by error it might be possible.
As I mentioned above, there is always overpressure from the nitrogen bottles to ensure a rapid inflation - that overpressure has to go somewhere - you can hear it escaping from vents after inflation (the same happens on survival dinghies).
There may even have been a leak in the feed from the bottles to the bags.