In line 1248/1249 (line numbers as in the Committee Specification Draft 02 / Public Review Draft 02) there seems to be an incorrect passage describing Retain Available:
"A Client receiving Retain Available from the Server MUST NOT send a PUBLISH packet with the RETAIN flag set to 1 [MQTT-3.2.2-14].“
If a client receives a CONNACK with Retain Available set to 1, it MAY send a PUBLISH packet with the RETAIN flag set to 1.
Only if Retain Available is set to 0, the client MUST NOT send a PUBLISH packet with the RETAIN flag set to 1.
A correction of the sentence could be:
"A Client receiving Retain Available set to 0 from the Server MUST NOT send a PUBLISH packet with the RETAIN flag set to 1 [MQTT-3.2.2-14].“