Line 2701 Table 3-12 - Unsubscribe Reason Codes
Reason Code 145 (0x91) is a in response to the entire UNSUBSCRIBE packet, and not for an individual topic filter. We need to allow in the spec to send this one independent of the list of Reason Codes. I suggest we allow one or more return codes in lines 2694-2696. The Server may send only 145 or a list of Reason Codes containing one return code per topic filter.
This issue was originally reported in MQTT-417, which doesn't seem to be applied in WD14.