crunchy section, why?

[sarahthegemini]

Today I washed my hair, I noticed that a part of my under layers is crunchy. Up near my scalp. It feels like I have used product and need to SOTC....but I haven't used any. Thing is, this happened before too, a couple weeks ago. Both of the crunchy sections were less than half a centimetre wide, and occured at different parts of my head. Which rules out the idea of build up. I'm rinsing just as I normally rinse, so that also rules out the idea of residue in my hair. Any thoughts what this is? It isn't terribly problematic, I can scrunch the section and it will be fine but I'm curious.

TIA!