My thoughts are that you may have had a burr on the threads to start with and
while tightening over the burrs caused the threads to gall allowing the nuts
to pass over the bad spot going on and not letting the nuts to come back off.
I try all nuts and bolts before installing to look for any rough spots and
either replacing or repairing prior to installing. Never seize or any other
anti seize wont cure this ill. I work in the abrasive industry and encounter
this problem every day and find this to work 99 per cent of the time. Also
cleaning the exposed threads prior to removal will get rid of dirt or any
other junk causing problems.
73 Mike W2GR
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