The issuancePremium() function in BasketHandler assumes that refresh() has been called on the collateral token in the current block. If this assumption is not met, it returns FIX_ONE instead of calculating the actual premium. While this is generally not an issue because the protocol holds this invariant, it can lead to inaccurate results when called from external view functions that cannot trigger a refresh(), such as RTokenAsset.price().
To improve accuracy and consistency, consider modifying issuancePremium() to calculate the premium regardless of when refresh() was last called. This would ensure more accurate premium values are returned even when accessed through view functions or external calls.
