The problem is, the shaft of the tie rod is spinning. You can take it back off, clean out the hole in the steering knuckle with brake parts cleaner, then clean off the exposed area of the tie rod end shaft with same brake parts cleaner, and THEN put it back together, putting upwards pressure on the tie rod end while you do it. That usually does the trick if you don't have an impact wrench handy.
--
Chris Herbst, in Wisconsin.

You are overtightening it if you are torqueing the tie rod end to 50lb ft. I
don't remember what the book has but probably around 40-42lb ft. at the most.

Also usually I have to put a jack up against the tie rod end and press it into
the knuckle because it won't seat in the knuckle tight enough by hand. That
way it won't keep spinning. This is the most likely thing happening to you.

Dave 82 242ti 278k mi.