[Eco Bounty] “Add Custom RPC” popup opens then instantly closes on Staking page

Wallet Address:
0x0f06443fbfc0Eb7D1f1c98DC74005546e2f70AAb

Bug Description:
On the Staking page, when the user clicks the icon next to the wallet address and selects “Add Custom RPC”, the popup briefly appears but immediately closes. It’s not usable.

Device & Testing Environment:
Device: Dell Laptop
OS: Ubuntu
Browser: Chrome

Steps to Reproduce:

1. Go to: https://hub.iotex.io/staking

2. Connect wallet

3. Click the icon next to your wallet address

4. Select “Add Custom RPC”

5. Observe: The popup flashes briefly then closes automatically
   

Actual Result:
The popup opens but then disappears instantly, preventing user interaction.

Expected Result:
The popup should remain open for user interaction until manually closed.