In all of the 1.13 pre-releases that I have tried out, including the most recent one, I have noticed that the application icon is no longer a crafting table as it used to be; rather, it is now showing my OS's generic .exec file icon. I am using a 2011 MacBook Pro running macOS High Sierra (Version 10.13.5). A picture is included below; look in the bottom-right corner to see the issue.

My apologies if this is a duplicate issue; I sincerely do not intend to clutter this site more than is needed. If this is the case, then that fact that I've found this website hard to use is probably why I missed it.