Follow up as I got the tire off the rim after work. Definitely seems like it's starting to split. But only on one side.
Is this indicative of being pinched by the rim? Ridden on asphalt trail 95% of the time.
Maybe the rim has a sharp spot, maybe the tire was damaged from that spot, maybe that spot was exposed to sun lot more and thus experienced more degradation from UV light, maybe just a shitty build quality of a tire
So many variables, but if you want to ride your tires as long as possible, keep proper tire pressure, keep the bike clean and protected from elements.
Great advice thanks so much! As I said above I think it was a combination of old tires, temperature and humidity changes and non true rim causing brake pad rubbing.