**Describe the bug**
Hi, I found something on the NanoMQ that is contrary to the protocol specification description (protocol violation or logic bug). 
For tracking purposes, I will report all results under this Issue.

**Environment Details**
 - NanoMQ version 0.21.8
 - Operating system and version: Ubuntu 20.04

**Client SDK**
If possible include the mqtt sdk you used to connect to nanomq
Minimal C test cases are perferred.

**Additional context**
Add any other context about the problem here.

Several protocol violations or bugs in NanoMQ
This is a GitHub Issue
repo:nanomq
owner:emqx
Title : Several protocol violations or bugs in NanoMQ
Issue date:

--- start body ---
**Describe the bug**
Hi, I found something on the NanoMQ that is contrary to the protocol specification description (protocol violation or logic bug). 
For tracking purposes, I will report all results under this Issue.

**Environment Details**
 - NanoMQ version 0.21.8
 - Operating system and version: Ubuntu 20.04

**Client SDK**
If possible include the mqtt sdk you used to connect to nanomq
Minimal C test cases are perferred.

**Additional context**
Add any other context about the problem here.

--- end body ---

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