Jerry, I've had the same experience. A Hagn single shot I bought recently had tiny lumps where the bubbles contacted the finish. I suspect the reaction may be finish specific, so perhaps some of the modern plastics would not react, but the oil finish sure did.

I'm going to go back to knit gun socks inside plastic boxes for all shipping I do, and request the same from shippers. It might add a few dollars cost, but worth it not to have to worry about saving the finish, original or not.