@ChrisDV  I checked the log entries (It's possible to download the log list in the "Export Data" section.)

The log is full of DHCP entries.  But as far as I can see, all DHCP logging notifications are turned off.   

Where can I find the function to turn off DHCP server logs?

I tried managing the router, but it is being controlled by the OC200, so no luck there.

I looked through all the Log Notifications and Gateway DHCP Events is already turned off.

  @ChrisDV 

 I find that if I leave the logs to accumulate, eventually the whole system will collapse. DHCP will stop working and I will be unable to manage the controller. 

That is probably also the case here. My whole infrastructure is very sluggish for the past few days.  Just received the "log full" email again.

It's possible to download the log list in the "Export Data" section.

Thanks for the tip, will have a look.

The logging system actually records log events that are set to "No notification" 

Probably yes, but the unchecked setting hides them in the logs? Weird behavior.

Update. Downloaded the log ist. Has 4365 entries. It has 1/3 of
"[client:xxx] was disconnected from network "yyy" on [osw:xxx:Switch](connected time:8m connected, traffic: 0Bytes)."

and 2/3 of 
"DHCP Server allocated IP address yyyyy for the client[MAC: zzzzzz]."

with recent time and date - last 12 days.

Nothing visible in the controller logs.

This is all disabled: 

Gateway DHCP Client Module Information

Gateway DHCP Server Module Information

Client Disconnect (Wireless)
Client Disconnected (Wired)

Definitely looks like a bug.

  @aly-fly  Yes.  I can easily reproduce two "weird behaviours":

1. When the log list is full, the DHCP system becomes unstable and I lose the ability to use local connection for management. The WAN link works because it does not use DHCP, but the system seems to be in a panic and functions extremely slowly until some log entries have been deleted. Then I can get control. 

2. The undisplayed log entries are just hidden. They are still in the Log List.  They can be deleted as a single action after you can control of the web interface, but until then you have to delete the 3 or 4 at a time using the phone app.

I discussed the problem with a Support agent.  I was told that there is an error in that the DHCP entries should not be being logged if the Notifications setting is unchecked.  I was advised to upgrade to the latest version of controller firmware, but actually I'm already running the latest version.  OC200 V2, 5.12.9,  2.11.3 Build 20230906 Rel.36272.

Why am I getting the problem but it has not been noticed by other people?  Well, I guess I have several hundreds of DHCP actions to new devices every day.  But also, we have 5 IoT devices misbehaving. They are causing DHCP actions every few seconds so the number of DHCP log entries builds up very rapidly.

Why does the system go into a panic when the log is full?  I don't know. Maybe it's trying to tidy the log, but the log gets untidy just as fast as it can be tidied. Certainly I have to clean the log list every day or we get severe performance problems.   

 I also have this problem and it's extremely annoying.  

Have the latest controller firmware. I have been following the issues for some time.  My logs are filled with DHCP connections(verified by export) and that's disabled. I archive/clean all and it gets filled quickly.  I get notified constantly its over the limit.  Its to the point I ignore the emails - boy who cried wolf scenario.   Please fix this BS!!  We are getting ready to buy more equipment but I'm not so sure about this support anymore!

  @Paulait  I don't have issues anymore since the last FW update of my OC200.

  @aly-fly  Agreed. The initial fix just stopped the warning but there was also a memory problem that seems to have been fixed by the update.

There is now an IP address problem and a significant delay in displayed data being updated with correct values.