The glitch is located in the Cave of Abaddon.

When you first go in there you should see a raised piece of rock in the middle with light shining on it and that is where you need to go.

Once there look for a chunk of bridge that is small next to a cliff about 6 feet high.

Jump on the shortest side of the bridge piece and then jump to the higher part of the bridge piece and then jump on to the cliff.

After that you can just walk out.

to get into the canyon but still out of the area you are allowed to go in then follow the canyon wall (while outside) until you find a way, some areas may fool you as the canyon wall on the outside is invisible.

It is pretty interesting to see some of the things the devs created that you normally can't get to.