I'm using the built-in scripting (Settings -> Scripting).

The WaitForCompletion function doesn't seem to do anything. Whatever comes after it in the script just happens immediately.

Function=Fade&Input=9b6381c7-156a-4f85-bdf2-d1faadc84979
Function=WaitForCompletion&Input=9b6381c7-156a-4f85-bdf2-d1faadc84979
Function=OverlayInput2In&Input=a061feb4-5d11-46df-9936-67d9a78f0384

The input is a 3-minute video. WaitForCompletion does nothing and Overlay2 comes on right after the video starts.

When I run the command as a Web API call from a browser, http://127.0.0.1:8088/api/?Function=WaitForCompletion&Input=9b6381c7-156a-4f85-bdf2-d1faadc84979
it waits until the video completes to give me the Function completed successfully message.

So the problem seems to be only with the built-in scripting (running it from a shortcut).

Any help is appreciated!