When publishing a post with a non-standard ASCII char (for instance, using RTL) the permalink appears with the character code instead of the character itself

To Reproduce
Steps to reproduce the behavior:

1. Go to a wp site and create a new post with an arabic title (which creates an arabic permalink). I use this to copy the text: https://translate.google.com/#view=home&op=translate&sl=auto&tl=ar&text=hello%20world
2. Publish the post with Gutenberg active
3. On the permalink field, see the codes there: http://cld.wthms.co/5sjUvt
4. Activate the Classic Editor plugin and head to the exact same post - the permalink appears with the characters instead: http://cld.wthms.co/rKe1Y8

Expected behavior
I expected the characters to appear as the title show them (as they'll appear in the URL).

Screenshots
Codes appearing with Gutenberg active: http://cld.wthms.co/5sjUvt

Chars appearing correctly with Classic Editor: http://cld.wthms.co/rKe1Y8

Desktop (please complete the following information):

• OS MAC Os
• Firefox