Opinions wanted - side wall 'wear'

Like the title says, what do you guys think? Normal or abnormal? Concerning or not?

Found some hair line cracks on the side walls of my tires today while doing something else. Thought it was just a small clean cut from a piece of shale initially, but the same pattern is present in the same location pretty much all the way around the tires. I do most of my offroad miles at lower pressures because, well, E range + small truck = no fun. But honestly we're only talking probably a few thousand miles offroad at lower PSI on these tires.

Seems a bit early to be having cracks like this show up doesnt it? Theres still a lot of tread left. From what I could see they were made in Q1 2016. But maybe running for extended periods at lower PSI takes a bigger toll than I thought..?

 

Another view. Same place all the way around:

 

Looks more like minor rock cuts to me vs "cracks" if so shouldn't be an issue....the BFG's on my FJ40 would end up being whitewalls if you ran them with the white letters out. Aired down in a rut and it would be easy to get shale cuts at the same general point all around a tire. The first pic especially looks like a rock cut. Pretty much cosmetic unless they get deeper.

 

What psi are you running? Alignment correct?

 

Did another ~220 miles on dirt this weekend. Need to clean the tires off and give them a look over, but no major issues.

Thats what I thought initially too. Seems too jagged and un-uniform (and in the same exact place on multiple tires) to be rock cuts, but I guess we'll see.

Typically will run right about 20 psi when doing dirt logging roads, enough to give a decent ride and some visible squat in the tires on level ground. And typically Ill run 100-200 miles that way in a weekend trip. Alignment is fine.