Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
I took the f27 sources and compiled them on a f26 system. Results are as expected so some other part in fedora 27 is the problem and this is not a ImageMagick bug.
Thanks for testing.