Accumulate + declared EntryPoint causes NullPointerException

When creating a declared entry point that uses a window, and using it with an Accumulate function in the same rule, this error occurrs:

org.drools.RuntimeDroolsException: Unexpected exception executing action org.drools.rule.SlidingTimeWindow$BehaviorExpireWMAction@57e40274
at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:995)

This error doesn't occurr when removing the Accumulate function or extending the expiration time of the window

A project that reproduces this error will be attached on the next comment.