Hmmmmm... Lots of theories going around here. I will add you just a little more info.

1) I live least than 1/4 mile to the nearest launch and usually launch about 4 miles away off smooth roads. I have made two trips to Eagle Lake in the last two years and the roads to Eagle are smooth.
2) The trolling motor bracket did not hit the roller. I would have noticed that for sure.
3) Once on the trailer, the boat is wenched tight to the rolled and has very little play if any.

I will say that if you have ever fished the rez, the waves will eat you alive. I have been on very rough water alot and it has taken a beating several times but it is made to be used.