It was both front and back rims on both fat tire bikes with random loose spokes. It was my front brake disk that was rubbing on one bike until I tighten the spokes. The rear spokes on the other bike was making the clicking sound when riding until I did the same for that. I come in at 280 lbs and another 10-15 lbs for rack+bag+tools. The wife at 130 lbs didn't get the same issues when riding.
I just got one of those
round multi spoke tools off Amazon for $3 and that seems to work pretty good. I have around 2000 miles on each bike and the haven't notice the working themselves loose after 1800 miles and 18 months of riding.