Rear air shocks leaking oil? Why?

Rear air shocks leaking oil? Why? It's been on the center stand for about a month, just noticed this

Would the air pressure inside the shocks force oil through any cracks?

I can't answer your question because I don't have rear air shocks, but I can say this issue was fairly common on Harley-Davidson air shocks a few years ago. In fact you had to have a "special" gauge to check them. Some air gauges are ruined if you get oil in them and you needed one that wasn't affected by oil.
Rick H.