Bug - Tabs - uncontrolled expandable doesnt have underline initially

[thatblindgeye]

Describe the problem
Reported by @Venefilyn on Slack, the selected tab indicator for the uncontrolled expandable Tabs implementation doesn't appear initially when expanding the Tabs list. You can select items fine and at that point the indicator works as expected.

How do you reproduce the problem?
Go to the uncontrolled vertical expandable Tabs example and toggle the expansion. Notice the underline indicator doesn't render until you click an item.

Expected behavior
The underline indicator should be rendered immediately upon expanding open the Tabs list.

Is this issue blocking you?
List the workaround if there is one.

Screenshots
If applicable, add screenshots to help explain the issue.

What is your environment?

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

What is your product and what release date are you targeting?

Any other information?