I created a script to change Assigned To based on another binding. In the following, when I select A for the first time, the Assigned to changes to Arpit Test, and Send for Review transition reflects that as well -

However, I get a notification that the Form is already assigned to Arpit Test in the existing Status.

In the scenario where I simply select the Assigned To from a drop-down, it doesn't assign it till the transition is used-