App.focus opens another instance of App in Mac OS Sierra/High Sierra

Any Idea regarding this issue? Thanks in advance

Pre-requisite:
"Some App" is already opened.
"Some App" supports multiple instances.

Using this code in Sierra and High Sierra:
App.focus<"Some App">

Actual : Opens another instance of "Some App"
Expected: "Some App" is focused. No additional instance is opened.

**Issue does not occur in Mac OS Mojave, Windows 7 and Windows 10