When creating an Input with webhooks, OBS seems to calculate the height/width of a source based on the sourceHeight/sourceWidth and ScaleX/Y values at the time of creation. So when it creates the source-clone input type and sets sourceHeight/Width to 1, you end up with a calculated height/width of 1 (assuming scale of 1). The clones are effectively invisible. But I don't know if that's anything you can fix or something solely on how webhook creation works on Inputs vs via the UI.
Adding to that is an issue where even if you stretch the clones out by manually editing the transform, something seems broken with them and they only ever show as black unless you fully restart OBS. So there may be even more going wonky under the hood that I haven't been able to sus out.
If it helps at all, 4 images attached.
Image 01: Manually created scene with 1 Colour Source and 1 Text Source, plus the Text Source's transform info.
Image 02: The duplicated scene using source clones, the Text Source Clone is now 1x1 and nothing is visible. (Swapping back and forth from the original scene doesn't fix anything, either)
Image 03: Manually adjusting the size of the Text Source Clone, showing that even the stretched source is still black.
Image 04: After restarting OBS, the cloned scene is now visible. One thing I just clocked is that the size increase of the Text Source Clone from Image 3 (308x308) has now been multiplied by the original source's dimensions (UI doesn't display the full number but after outputting the scene item information the Text Source Clone is 174,328 x 38192 (566 x 124 scaled by 308)
Starting to think it may just be an incomplete creation step on webhooks' end that is only corrected once OBS rebuilds everything on restart?
(Use and love a bunch of your plugins, they're all fantastic!)