P: Clarity Issue

Hello, I have some strange behaviour with the clarity effect in
Lightroom 2015.8, different from the 5.5 version. If I use the adjustment brush with clarity it darkens also the area. It seems that this happen when a radial filter with exposure adjustment has previously been applied in the area where the clarity brush is applied. I post a video that shows clearly the problem.
This problem in Lightroom 5.5 doesn't exist, as shown in the video.
Thank you

Edit: It seems that the web control doesn't let to show the video in full screen, this is the link: https://vimeo.com/203712701