ProgressBar percent variable not working since 4.12

I’ve tried to use the percent variable from a progressBar in UE4.12, but it always returns 0. I tested it also with version 4.11 and there i’ll get the correct percentage value.
On the screenshot you can see an example of the problem.

Got the wrong section.
Here is the link to the bug report section: https://answers.unrealengine.com/questions/445115/progressbar-percent-variable-not-working-since-412-1.html