Rules execution from BusinessRulesTask much slower than in test case

Issue

We have a kjar with a large number of rules. In our junit test, we are inserting all required facts, and get a result in ~1 minute. This is ok from a performance perspective, given the high complexity of our rules.

But when executing the same rules, with the same set of input parameters, inside a BusinessRulesTask from within a jBPM process, the server is running into a transaction timeout after 5 minutes, before the rules execution has finished. Why is it taking so long to execute the same rules with the same facts in the context of jBPM?