The first two was bought from a retail store: https://shopee.ph/Tp-Link-Deco-M4-2-pack-AC1200-Whole-Home-Mesh-Wi-Fi-System-i.6562415.2726707742 And the last one was bought from an individual seller...

I have a 2-pack Deco M4 initially installed and I updated the firmware to the latest one 2 days ago (1.5.0 Build 20210511 Rel. 34580) Today, I bought another M4 unit and installed it as a new...