Target Browser Source for $movie

[cattywampus04]

Hello

Simple problem that from the help docs suggest this is possible, but I can't get it working.

I would like to have multiple browser windows of different sizes on my scene in OBS, each to play different kind of custom videos (e.g one sized for the bottom right quarter of the scene and another is the full size of the OBS scene).

I have tried using a command like this in Streamlabs Chatbot:
$movie(NameOfFile.webm,0,2,CLP1)

I name the browser source in OBS to "CLP1" and the other to "CLP2" and it does not working. It plays in neither of them.

Am I missing something here?
Thanks.