I've heard that a few people have used POE oil with propane/R290 and had no problems.
But, I have not heard of anyone using that mix long term.
IIRC, some of the over-clockers have used propane with POE oil and it worked.
And, it seems like pulling a good vacuum on water-loaded POE does remove some of the H2O.
(The last half of the video is the most dramatic)
I used a long vacuum run on my repaired Sanyo (leaker) and then used a filter-dryer
to try to clean up the R410A and the old POE before use.
That was last fall, and it's still running pretty well. But, only time will tell.