The three usual causes
First: silicone or similar coating applied at the factory to make processed hair feel smooth. Colour services strip it and the underlying condition appears. Second: undisclosed prior processing — hair already depigmented once cannot take a second aggressive service. Third: direction faults that were tolerable while the cuticle was smooth and become matting once it is raised.
All three are supply-side, and all three are invisible in the first sample.
Diagnosing it
Take an unused piece from the same lot. Clarify it twice, dry it, and run the wash-cycle test. If untouched hair from the same lot fails after clarifying, the problem was in the material, not in your service.
Keep the lot number. Without it neither you nor the supplier can trace anything.
Preventing it
Buy hair whose processing history is written down, and clarify a test piece before you promise a client a colour service on extensions. Ask suppliers directly whether any coating or conditioning finish is applied before packing.
We state processing history on the specification and do not apply masking coatings. If our hair will not take the service you have planned, we would rather tell you before you book it.
Buyer Questions
Can I tone your hair in the salon?
Yes, within the stated processing history on the specification. Ask us before planning a lift on already-lifted shades.
Do you apply silicone finishes?
No masking coatings. What you feel in the sample is the hair's actual condition.