[rules-users] Mvel compilation error

Hi All, We are intermittently getting mvel compilation errors with the following: Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39 ) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl .java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.mvel.optimizers.impl.refl.MethodAccessor.getValue(MethodAccessor.java:61 ) ... 148 more The rules compile ok and the application will run normally (rules processing successfully) for a few days then this error will occur. Tried to replicate but once the application is restarted the last action before the failure is repeated and always processes successfully. Any help would be appreciated. Regards JS