FBM not eligible for buy box?

I have two products as FBM but it’s there’s a section on Seller Central that says: “Feature offer eligible” and it’s automatically marked as “no”.

I’m wondering if anyone has ran into this issue before and what solutions did you use?

Background: I have done a lot of FBA and they are all eligible for the buy box. My account has been opened for about 6 months. Approximate number of transactions are about 800 I think.

Account health is green at 208 and no issues so far with selling on Amazon.

Thank you for all insights and advice.