Extender mode proxy ARPs for device IPs on WiFi Network?

Technical Support for Routers
1

Picked up a GL-MT300N-V2 today, intending to use it to bridge a wired ethernet device into my WiFi network. When I configured it in ‘extender’ mode, crazy things happened, as it started sending ARP announcements for essentially every device on the WiFi network:

|12/19/2022 10:39:12 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.10.202|
|12/19/2022 10:39:13 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.53.5|
|12/19/2022 10:39:15 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.10.201|
|12/19/2022 10:39:15 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.4.12|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.4.8|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.3.15|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.4.6|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.4.7|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.3.12|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.10.203|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.3.19|
|12/19/2022 10:39:16 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.10.204|
|12/19/2022 10:39:17 AM|Flip flop|94-83-C4-1F-9D-6D takes other’s IP: 10.0.0.1|
etc…

That last one here is the gateway… so this caused all kinds of bad things to happen.

Did I do something wrong? Or is this some kind of bug?

2

So you didn’t set anything else except for as extender?

It is rather strange for this behavior.

3

From a factory reset, all I did was hit ‘scan’ on the wifi, connect it to my wifi network, then set mode to extender. As soon as it came back up I received those messages from arpwatch.