I looked at the file, a developer might need to look as well, but this appears to be working correctly overall. The -1 offset tells the thickness setting which direction to go, so a positive thickness will go on the back side of the faces, that's why you always see the wires, because they remain on top. An offset of zero splits the thickness front and back, so in reality you shouldn't see the wires at all, so it might be some sort of internal clipping thing. 1 for an offset allows the thickness to be projected from the front of the face, again covering the wires. The display has been this way in the 2.8x series and 2.79 series as well where sometimes wires are shown at certain distances or with certain thicknesses of meshes at particular scales. May be OpenGL related(?)

In defense of everybody, it was my fault for testing something specific, and felt it was related somehow, thus posting it into the same bug, for I intended on showing that with different geometry the original bug remained, however I had deleted that release and tested a new one. In my coding ignorance this seemed like a regression of some sort. I will post separate issues in separate reports in the future. I apologize for the confusion and greatly appreciate all of the hard work each and every one of you do. I wish I could contribute more, but I am limited to bug reporting. Thanks again, and continued support for making a fantastic product.

Now I get a crash when subdividing and then trying to enter edit mode

This error still exists with the build that I down loaded immediately after your reply.

Tested and found resolved in hash 55e3c17ccc1 on the file that I originally provided for testing, as well as others.