in a single operation, you can only check the feature flag once. This is because if you checked if the feature flag was enabled multiple times within a single operation, it's possible that the feature flag and FCV might have become enabled/disabled during that time, which would result in only part of the operation being executed.

Currently, it's up to the writer of the code to make sure they only check the feature flag once. We should investigate making this safer by default. For example, we could investigate stashing the result of the feature flag check on the OperationContext so we get a repeatable read for a given operation