RL error with transition on activation

I had transitions configured on two different RL apps. This caused them to throw the following error:

[app:426])org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'null' with class 'null' to class 'int'. Try 'java.lang.Integer' instead on line 3368 (method actHandler)
[app:426]Activation Event: 'Bedroom Motion' motion active

Removing the transition resolved the error. Now, I am unable to recreate the error when putting the transition back in.

I am confused by the difference between "Use transition for activation" and "Device Transition time".

Some devices allow a specific transition time to be included in commands to the device. This is "Device Transition time".

"Use transition for activation" is a software based sequence of steps to gradually change the devices.