glad to see I am not the only one to have this problem.
Same here. I actually posted a message on it.
It often happens on 'public' networks or networks of the "Fon" type, i.e. other users share a public part of their WiFi router with me.
(In my particular case "WiFree" in Belgium or "Ziggo" in other European countries).
I actually had the idea that the Gemini gets confused when multiple emitters use the same name. It doesn't necessarily pick the strongest one and then starts to drop off and reconnect.
In the end, it's the error you describe here above.
Let's hope that future Android updates fix this.
My wife's Huawei with Android 8 has less trouble (but sometimes does show the same behaviour nevertheless).
It would be nice if we get the Gemini to pick the strongest signal and then to 'lock' onto that one particular emitter.