Starttime and endtime not set properly

Using flowable 6.4.1

Sorry for the late kick but this doesn’t work for me trying to use a custom clock.
If I create a custom process engine then flowable doesn’t start complaining that “CMMN engine has not been initialized” in CmmnEngineServicesAutoConfiguration. It looks like it expects me to also create a custom CMMN and app engines? This opens a whole can of worms and flowable doesn’t even start.

There was mention of setting CURRENT_TIME but that is quite hacky. It is relying on the fact that setting the time sets a static variable for an object that might have multiple instances.

I want to use a custom clock.
I currently have it working by using reflection to set the clock, variableServiceConfiguration.clock, jobServiceConfiguration.clock field in the beans of ProcessEngineConfiguration, CmmnEngineConfiguration.

This is obviously not ideal. What would be the proper way to use a custom clock in flowable?
My use case is to test - amongst others - timers in an acceptance test environment.