Remember POE oil doesn't mix with other oils including vacuum pump oil. So, you are likely seeing a mix of water vapor, and oil droplets.

Boiling the oil itself would have to have a seriously low vacuum, but because POE oil won't release water easily, it likely will hitch a ride with the water during evacuation.

Problem is, it will be difficult to remove all moisture from the system.

I think it would be best to come back and replace the drier after a week or so of run time. At least perform a moisture test.