Well I guess you're right about the caprylyl glycol... I didn't even know it was a humectant! The thing is, for whatever reason only glycerin has given me issues. And even then, if it's listed after an anti-humectant (as in the case with the Alba Botanica leave-in) it hasn't given me problems.
These are the Curl & Style Milk ingredients on my bottle:
Deionized Water, Shea butter, coconut oil, sugar starch, silk protein, essential oil blend, neem oil, caprylyl glycol, sorbitol esters, algae extract, hyssopus oficinalis extract, sage leaf and equisetum arvense extract, carrot seed oil, honeysuckle and Japanese honeysuckle flower extracts, tocopherol, hibiscus flower extract.
My ingredients are different than the ones listed in the products section of this page!
The first two (non water) ingredients are both anti-humectants so one humectant in the middle of the list shouldn't be an issue.