It could be other ingredients or not enough DT's. I have tried clarifying when my hair gets like this. It usually works.

I have also found that my hair needs protein on occasion but my treatments consist of protein rich conditioner that I work through well but do not leave on for any length of time...seriously, I work it through (fingers, wide-toothed comb, Denman) then rinse. And I still follow with a DT. It's all my hair can handle. So, it's possible if you did a strong PT that it is from that.
remember, with all advice or suggestions for your hair, YMMV!!
My hair:
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
My routine:
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)

Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.