It was tied correctly, it just is a horrible knot for life support, or honestly even rigging. It works on trees, but there are far better options, a bowline with a lock hitch is better with less rope. It is completely abhorred in the construction world, because it will kill someone if done on the wrong rigging setup, even tho half hitching is completely fine. It was also pointed out that whenever you are pulling an eye in more than one direction it is better to use a link designed for such loading, such as a shackle, rigging ring, master link, sling grommet, certain knots, etc. A spliced eye or really any eye on a strap, especially nylon since it's stiched but even stamped wire commercial wire chokers will come apart if the eye is loaded like that. If slack is twisted out of your timber hitch during climbing (all but guaranteed), your spliced eye could be spread apart, likely killing you.
Edit: looked at it again and i see that it isn't even choked.