Why can't I leave an old sync chain?

I have been using Brave on both my PC and my android and bookmark synced them for a month now.

Well I started using Brave on my android first so, I created a Sync chain on my android and now that added my PC. And now I want and tried to remove my android from the Sync Chain but it does nothing and I’m still on the sync chain.

My android is on Brave 1.9.80, Chromium 81.0.4044.138