The past few months I've noticed an issue where two devices on my network, an HP printer and a Visio TV, frequently disconnect from my Eero network and can't rejoin the network.  In the case of the printer, I have to turn off the printer and turn it back on to get it to join the network, which it does automatically.  In the case of the TV, I have to restart the entire Eero network and then manually re-join the TV to get it connected again.  I did check and the printer firmware is the latest version, which was released in 2015 (and no updates available).  The TV I am not sure about as I have not checked yet.  My eeros, which are first gen, are running eero OS v3.7.0-948.  I'm not certain it's the network, but I'm starting to suspect it's the network as I have two devices (that I know of) having issues like this, and at least one of them has not had updated firmware.  The eeros do receive regular software updates, which is why I am thinking it's "plausible" that an eero OS update introduced issues for these devices.