[rules-users] Any limitation on the count of properties when declare new class in drl file?

Hi, I encountered a strange problem these days, I declared a new class a.b in drl file using keyword "declare", it has too many properties, larger than 64, then when fire rules, it threw ClassCastException, told me class a.b cannot be casted to a.b, but actually these are same class. I tried to remove some properties made it less than 64, no CCE when fire rules. This just happened in my product environment, if I run the rules in a pure drools environment in Eclipse, no exception even the count is larger than 64, anybody know why this happened? The version of drools we used in our production is 6.0, we forked the code from GitHub, so maybe it's not up to date. Thanks, Richie