07-02-2018, 06:21 AM
Can't reproduce that, even after tputting the smudge tool in the same settings as you. Can you reproduce that on a small image (say, 200x200, with as few layers as necessary) and upload the XCF (your are allowed 2MB upload for XCF, you can also save using the XCFGZ or XCFBZ2 formats, that are compressed).