Attached is a video of how to reproduce the problem on UWP.

Steps to repro

1. Open SDKExamples > AutoCompleteView > Key Features
2. Select a value for Tokens Support
3. Select a value for Filtering Behavior
4. Start to enter a value for Watermark, but do not auto-complete it (leave the popup open and go to the next step)
5. Click back into the Filtering Behavior box

=> Observe the infinite loop.