Remove Random Border that Appears When Blur Filter is Activated

I am blurring the license plate on a video. Everything is normal without the blur filter, but when I activate it a black border around the selection appears.

I have not changed any setting to turn this behavior on, nor can I find one to disable the border.

What I have done to troubleshoot:

  1. Tried this with another video clip. It produced the same result
  2. Toggled the other filters on and off. The blur filter is definitely the one that causes this problem. No border exists otherwise.
  3. Browsed through the menus for a solution.
  4. Browsed through the toolbar for a solution.

Specs:
Windows 7 OS
Running Shotcut Version 17.12.03

Any help you can provide would be appreciated.

Here are some images that illustrate my problem:

Without blur -
[EDIT: Removed image because it was showing a license #]

With blur -

I am also having the same problem.

So… should I tag this as a bug?

It’s just to show the zone. When you export, it shouldn’t be there.

No, it still shows the same. Try it yourself and see.

Yeah, it’s still there after export

I tagged it as a bug.