[JRTJH]

Typically, at least from my experience with trailer wheels, steel wheels have "open lug nuts" with plastic caps and aluminum (mag) wheels have closed lug nuts that don't need caps. The closed lug nuts are like the ones in the pictures provided by littleking. I'd suspect (from looking back through the previous posts about this trailer) that either the OEM wheels were exchanged at some point or the trailer was delivered with aluminum wheels/closed lug nuts at the 4 axle ends and with a steel wheel (that requires open lug nuts) as a spare. Trying to use closed lug nuts that fit a wheel that's 3/4" thick (so they tighten against the wheel) on a steel wheel that's 3/16" thick will cause the lug nut to "bottom out" against the lug before it tightens against the thinner wheel. So, you'll never get the lug nuts to properly tighten against that wheel. Essentially, it's two different systems for installing the wheel on the axle and they aren't interchangeable.

This is another example of why I suggest "new owners" actually go through the process of changing their spare tire to an "on the ground" position on their trailer "IN THE DRIVEWAY" before they have a need to do it "on the side of a busy highway".....

While one could say this is "no fault of the owner", reading the problems with this specific trailer and the lack of service from the dealer, going all the way back to 2014, I'd have to say that this problem doesn't surprise me, given the history of the unit.