Thank you very much for choosing our theme and for contacting us.
1. You have two rows in the header, you have made the bottom row and middle row not sticky, as the result, you see one row on the sticky header: https://gyazo.com/789714a1a23f97258d7cb58bed92c76c and https://gyazo.com/7014f4880f14414dfdeb7db0b981b691
2. Could you kindly provide the product page URL so that we could check?
3. We will check and get back to you on this issue.
If you have any questions please feel free to contact us.