Bad Stale not tag related

I got an Overlay Error, on a popup on an embedded view.
Its from style class of dropdown component.

This style class is bind, such that, one style class is use over the other, depending on some logic.

Why is this error? Why is this one stale? (intermittent though 1 out of 8 popup launches)
image

Edit:
I tried reducing the logic by utilizing front views custom parameter.
still shows the error.

I'm guessing in one particular case the class doesn't get any value, either because the binding fails to evaluate or because you're missing a case in your logic.

If you are able to post a screenshot of the binding configuration that could help.