@RedRoger 

Hi, have you tried to turn off the Mesh Technology on the Redmi 9 to have a look?

And may I know the operating system on the Redmi 9 as well?

@RedRoger 

Thank you very much for the updated information.

 I would like to follow up on your case by email and please have a check of your email box later;

Thanks a lot.

@BananoMX 

Hi, Have you tried to turn off the private/random MAC address on the smartphone to see whether it improved the stability?

 And I also checked the engineers and they explained that:

When a device is roaming between Decos, there will be a disconnecting and reconnecting process, but some devices have a shorter switching process, so you will not feel it. Please note that this behavior is determined by the client. Deco supports the 802.11k/v/r roaming protocol, which can reduce the roaming switching time and improve the roaming experience. So the client must support the roaming protocol to roam in a very short time as well. If the Wi-Fi switching process is felt on the mobile phone, it may be caused by the mobile phone not supporting the 802.11k/v/r roaming protocol. Generally, the roaming process does not affect the Internet access because it won't take a long time to roam from AP to the other one, but it may affect the application that requires low network delay, such as VOIP phone.

And for more details about the roaming protocol of Deco, please refer to the following link:

Get to Know Fast Roaming / Seamless Roaming on a Deco System

@RedRoger 

Hi, Could you please do me a favor and save the system logs when the Xiaomi Redmi 9/ Mi 9 are disconnected from Deco?

Please also help me note down the time when you noticed Xiaomi Redmi 9/ Mi 9 phone are disconnected.

 By the way, would you please also give an update to ticket ID # TKID210330037

And for other users, it would be highly appreciated that you could save the related log and note down the disconnected time as well.

Thank you very much.