Bluetooth disconnects when I switch wallets.

This is normal behavior. When you switch to a passphrase wallet, the Bluetooth connection drops briefly and then reconnects.

[Notes]

This keeps the connected mobile app from continuing to show the previous wallet's information.
Once it has reconnected, the account information of the wallet you switched to is synced with the app.
If it does not reconnect automatically, turn Bluetooth off and on again in the Control Center and connect from the app.