Unwanted, unkillable text/media boxes in Presenter 360

Hey folks.

I am completely new to the Articulate suite and I am starting with Presenter 360, since I am familiar with Power Point and have Office Professional Plus 2016.

While creating my first presentation, I encountered an issue where it looked like Articulate was creating new empty default PP content boxes on the slide where there weren't any before. The first attached picture shows an example. The box cannot be deleted. If it is resized, rotated, moved, or copied, it creates a new box and leaves the original one in place. The new box can be deleted, but the old one stays. This is also true if I add text to the box - it creates a copy with the text that can be deleted, but the original stays. Once one of these boxes appears, restarting the program doesn't get rid of it.

This was a minor irritation until a picture was accidentally inserted into the box. I added pictures from the media library to a couple of slides and everything was fine. Then, on one slide, the picture was added to the unkillable content box, and now I can't move it or delete it.

I am prepared to rebuild the slide and delete the old one in order to move forward, but I don't view this as a viable long-term solution to the problem. Is there anything I have missed?

Thanks,

Seth