Does anyone recognize these spots I've found on my tree? They're mostly flat (slightly bumpy texture) and shiny, and I can scrape them off with a fingernail fairly easily. They all have the three white lines radiating outward. It's a water oak, maybe 10 years old. I've done a bunch of searching online but I haven't found anything that matches. I've also had a couple arborists out to check out my tree (looks like it's got a nutrient deficiency and crappy clay soil, but is otherwise pretty healthy) and neither of them recognized it. Maybe it's just not common in my area? Any help is appreciated.