When mutations for a column family is about to be applied, the cached instance of the keyspace metadata is read. But the schema mutation for durable_writes hasn't been applied to this cached instance.
I'm not too familiar with the codebase but after some debugging (2.1.3), it's somehow related to:
Where a cached instance of the keyspace is opened but it's metadata hasn't been updated with the earlier applied durable_writes mutation, since it seems that the cached keyspace instance is lazily build at startup but after that, never updated. I'm also a little bit concerned if other values in the cached keyspace instance suffers from the same issue, e.g. replication_factor...
I've seen the same issue in 2.1.5 and the only way to resolve this issue is to restart the node to let the keyspace instance cache reload from disk.