Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 6.1.0
• Cross-platform modules: 6.1.0
• iOS Runtime: 6.1.0

Describe the bug
When tapping on the tab strip tabs one by one, they get stuck at the second.

To Reproduce
Playground example:
https://play.nativescript.org/?template=play-tsc&id=prISaT

1. Tap on second tab.
2. Tap on third tab.
   Result: the highlight is stuck on second tab and the page tab isn't slided.

Expected behavior
Should move to third tab.