WAB removes widget and leaves empty container space

[MollyJordan]

Just wondering if anyone on here has run into a WAB Developer bug or something similar to what is happening to me. 

I have multiple custom apps built on a "Foldable Theme" with a custom (??) layout. 

Every once and a while (not every time, its sporadic) when I go into my apps to make a change or edit/update the app it will remove the bottom left widget and leave an empty container space. From there on out, it is as if it does not exists. I cannot add it back in our see the container anymore. I have to create a new app.

Any help or suggestions would be great. 

Molly