Thanks for pointing out. Here is how the Text Shortcut works. It is a storage list, if your shortcuts were in different Unicode they will stay same after changing the language. You can try by creating another shortcut “bsm2" in Arabic’s EuroNaskh typeface and then switch to Urdu typeface and see how it works?
There are many things beta tester cannot find that’s why there is always an update. I am sure you already submitted that bugs to Apple? They will take care of it. Nothing is perfect in first go.