I may be wrong in my assumptions here, but I always understood that VPI was essentially a very light, easily vaporizable (is that a word? I don't know) oil.
Oil vapor will, over time, kill primers. I've seen it happen.
If, however, VPI isn't oil, then it may not be an issue.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.