Groups have moved within a frame file is reopened

Hello

I'm using Animate 19.2.1 on a Mac and have noticed with increasing frequency that groups I have drawn have moved when I reopen the file.

For instance pupils will have moved out of position, or noses will have gone higher on the face.

A recent file had character arms detached from the body, ears floating in mid air etc

Happened on most keyframes 

I was drawing them as groups on the same layer with the paintbrush tool and have attached a picture to show a frame before and a screenshot of what I saw when it was reopened after saving