@AndrasN Glad it worked for you. This is the only time you needed to follow that process: since firmware 1.5.* the button "Update Deco" is working in Deco app. When TP-Link releases next firmware for...

@MatteoArlo Would you consider switching Deco mesh to Access Point mode? That should eliminate this issue. How to set up Deco to work in Access Point mode If you take that route, remove Main Deco...

@MedMez I have no experience with ubiquity networking gear, but maybe @Philbert can lend you a hand with that.

@ZestforLife It is my understanding that anything connected to Deco Guest Network will not be placed in offline devices list when it disconnects. Check that: enable Guest Network in Deco app,...

@AndrasN You appear to be technically savvy, so here is another option for you to try: firmware recovery, with the latest firmware file from the TP-Link Support page. How to use firmware recovery if...

@BobInIdaho I would point at two things: 1. "50 feet away" is at the end of recommended distance for Satellite Deco. See Q2 in General question about the Wi-Fi range of Deco. In simple terms, it...