Changing replicas to 3 when durability is set displays error on document save

Setting the durability to a value, like persist to majority, with the replicas set to 3, then trying to save a document causes an error. 

The docs say CB doesn't support durability when replicas are > 2. However, there doesn't seem to be anything from stopping me from configuring the bucket that way. When I set durability level in the bucket config to persists to majority, then make the replicas three, I can do a rebalance, view docs, etc. However, when I try to edit a document and save it, the error below is displayed.

It seems that if CB doesn't support that configuration then the app should prevent one from getting in that state, or at least warn the user of undesirable consequences. 

https://docs.couchbase.com/server/current/learn/data/durability.html
Couchbase-Server durability supports buckets with up to two replicas. It does not support buckets with three replicas. If a durable write is attempted on a bucket that has been configured with three replicas, the write fails with an EDurabilityImpossible message.

Errors from server: {"headers":{"normalizedNames":{},"lazyUpdate":null},"status":500,"statusText":"Internal Server Error","url":"http://localhost:8091/pools/default/buckets/david/scopes/davids/collections/davidc/docs/key%3A%3A1","ok":false,"name":"HttpErrorResponse","message":"Http failure response for http://localhost:8091/pools/default/buckets/david/scopes/davids/collections/davidc/docs/key%3A%3A1: 500 Internal Server Error","error":"[\"Unexpected server error, request logged.\"]"}