Hello,
Thank you for your report. rotation lock is a known problem that we are working on fixing. It has been assigned to a developer to be resolved, but until then there is a known work-around in Blueprints that was described here:
“One blueprint setup we have been able to use to create a day/night cycle is using a Timeline that modifies your directional light’s rotation with a Set Actor Rotation node. You can setup a float in your timeline that goes from 0 to 360 (or 0 to -360, depending on which axis you’re rotating around) and control how quickly it does that rotation within timeline itself. If you would like an example of what that would look like in a blueprint, let me know and I’ll provide a screenshot.”
If that does not help, could you please describe what you would like to accomplish so that we can find a better solution?
Thank you,