There is a problem with resize button and how they are working now compared with official release. The stretch button do nothing, while the scale (that should be proportional) now stretch a cropped image. Was working on 13.1.3
OS version in case that's relevant. Also perhaps it's related to the handling of the input device as it works as expected for me on macOS 10.14.6 with a webcam.
CraigS Catalina 10.15.5, MacPro 6.1, Canon EOS 600D via Blackmagic Mini Recorder.
I'm on Windows10, WC 13.2 Beta 2, and the Stretch to Fit button is non-functional for me, too.
Thanks for reporting. Investigating.
Link to Old Telestream Community Forum