Cannot set embedded canvas app to tablet enabled

Hi,

I have successfully embedded a canvas app in a form for a model-driven app, however I have an error when trying to enable the control for phone and tablet. I've circled the options below I'm trying to set...

I only have one embedded canvas app, but when I select the "Phone" and "Tablet" controls in the "Field Properties" section I get the following error:

"You have more than one canvas app with Phone form factor, the maximum is one for this form factor. The number of canvas apps are limited to three for Web and one for Tablet and Phone form factors."

The form used to have a different embedded canvas app in it (for which I could select Phone and Tablet), however that has since been deleted. The only thing I can imagine is that there is a bug such that that previously deleted canvas app is preventing me from setting the new canvas app.

How could I resolve this?

Thanks.