As demonstrated by this test https://github.com/kiegroup/drools/blob/master/drools-compiler/src/test/java/org/drools/compiler/common/MarshallerTest.java#L207 an accumulate rule doesn't refire after deserialization. However if the accumulate contains more than one accumulating function, e.g. the accumulate in that test is rewritten as 

 accumulate ( Person ( getName().startsWith(\"M\"), $age : age );
              $sum : sum( $age ), $max : max( $age )

it mistakenly fires once again after deserialization.