Fixed incorrect backoff docs

nats-concepts/jetstream/consumers.md

@@ -63,7 +63,7 @@ was introduced. The `Editable` column indicates the option can be edited after t
 | InactiveThreshold | Duration that instructs the server to clean up consumers inactive for that long. Prior to 2.9, this only applied to ephemeral consumers.                                                                                                                                                                                                      | 2.2.0   | Yes      |
 | [MaxAckPending](#maxackpending) | Defines the maximum number of messages, without acknowledgment, that can be outstanding. Once this limit is reached, message delivery will be suspended. This limit applies across _all_ of the consumer's bound subscriptions. A value of -1 means there can be any number of pending acknowledgments (i.e., no flow control). The default is 1000.                          | 2.2.0   | Yes      |
 | MaxDeliver        | The maximum number of times a specific message delivery will be attempted. Applies to any message that is re-sent due to acknowledgment policy (i.e., due to a negative acknowledgment or no acknowledgment sent by the client). The default is -1 (redeliver until acknowledged). Messages that have reached the maximum delivery count will stay in the stream.                                                                                                                                                                                                          | 2.2.0   | Yes      |
-| Backoff           | A sequence of durations controlling the redelivery of messages on `nak` or acknowledgment timeout. Overrides `ackWait`. The sequence length must be less than or equal to `MaxDelivery`. If backoff is not set, a `nak` will result in immediate redelivery. E.g., `MaxDelivery=5` `backoff=[5s, 30s, 300s, 3600s, 84000s]` will re-deliver a message 5 times over one day. | 2.7.1   | Yes      |
+| Backoff           | A sequence of delays controlling the re-delivery of messages  on acknowledgment timeout (but not on `nak`). The sequence length must be less than or equal to `MaxDelivery`. If backoff is not set, a timeout will result in immediate re-delivery. E.g., `MaxDelivery=5` `backoff=[5s, 30s, 300s, 3600s, 84000s]` will re-deliver a message 5 times over one day. Note that backoff is NOT applied to `nak`. A `nak` will result in immediate re-delivery unless `nackWait` is used to set the re-delivery delay explicitly.| 2.7.1   | Yes      |
 | ReplayPolicy      | If the policy is `ReplayOriginal`, the messages in the stream will be pushed to the client at the same rate they were originally received, simulating the original timing. If the policy is `ReplayInstant` (default), the messages will be pushed to the client as fast as possible while adhering to the acknowledgment policy, Max Ack Pending, and the client's ability to consume those messages. | 2.2.0   | No       |
 | Replicas          | Sets the number of replicas for the consumer's state. By default, when the value is set to zero, consumers inherit the number of replicas from the stream.                                                                                                                                                                                      | 2.8.3   | Yes      |
 | MemoryStorage     | If set, forces the consumer state to be kept in memory rather than inherit the storage type of the stream (default is file storage). This reduces I/O from acknowledgments, useful for ephemeral consumers.                                                                                                                                   | 2.8.3   | No       |