Tab changes losing data-binding (reactivity)

I have an issue.

I have two tabs, Tab1 and Tab2

In Tab1 I have a variable counter.

By default I am loading Tab1 , which also has a button, on clicking it increments the counter.
In Tab1 there is also a label, which displays current value of counter.

Now issue is, if I switch to Tab2 and back in Tab1 again, it breaks data-binding of label, i.e. if I click on button in Tab1 now, it still increments the counter but not reflecting in the view (Label still shows old value)
Please help about the matter