Bad keypair after lock & unlock

[h4x3rotab]

Re-pro

• Create two accounts (A, B) in PolkadotJS UI
• Unlock wallet with A
• Now we can see the balances in dark wallet
• Lock wallet
• Unlock wallet with B

Symptom

The dark wallet balances don't get updated. Open the inspector and get keypair error:

I suspect the lifetime management of the keypair is incorrect (not replacing the old keypair with the new one)