Bug: Function apps IP Restrictions blocks portal UI

I noticed that if you set a IP restriction to a Azure Function app, you block the Azure Functions portal user interface at the same time.

Original goal

I found this bug while trying to restrict IP addresses to Logic Apps in my region (Western Europe).

Error message

Error: The function runtime is unable to start. Please check the runtime logs for any errors or try again later.

Reproduce

1. Create a Function app

2. Goto Function Apps -> Platform features -> All settings -> Networking -> IP Restrictions

3. Add a rule, for example: IP address 40.68.222.65 (Logic Apps in Western Europe)

4. Go back to Function Apps

5. Error message appears