The lighting of shulker bullets is too bright in the Overworld compared to shulker bullets the End and the Nether. Attached screenshot has more detailed information.

Update 1.10.2, 16w43a & 1.14.4:
In the End, the light randomly can be too bright and have normal brightness.

Update 19w45b:
Not as bright as they used to be, but brighter than in the end. Also, shulker bullet brightness rendering in the End no longer seems to have any issues.