@skyclud,
Thank you again for the report. So it seems that at this time there’s no way to do this. That said, we have opened the following issue to include this option in future updates:
Additionally, it’s worth noting that even though that device is still part of the chain, it shouldn’t cause any issues with new devices added to the chain or that are currently on it. You can also use the Leave sync chain option on both new stable browsers, then create a new chain with only those two.