The 100% het clown means that one of the parents was a clown. The other parent was either het or just not carrying the gene.
If you breed that snake to a clown, 50% of the babies will be clown. The rest will be 100% het.
If you breed that snake to another het, there's a 1 in 4 chance of the baby being clown. The rest will be 'normals', but 2 out of the 3 left will be 'het' and carrying that clown gene. The only sure way to tell which one is by breeding them to a het or a visual clown.
The addition of banana and pastel complicates things a bit more.... but that's how a clown pairing works.
Hope that helps!