The cleanup for the content widget is not done properly.
The issue is that if you edit an asset (tested with dataformat), and then open another dataformat without saving the previous one the content of what you have opened past will be shown in the one that has not been saved, instead of it being in the previous state.
I realize that you don't even need to make a new dataformat. To reproduce the issue, you just need to have several dataformat from one or more than one user available. Start opening them one after another and look at the change in the content!
The issue comes from how the widgets are being cleaned before a new asset is open. The content from previous asset is not cleaned fully and what you see as the newly open asset is not it's own content but information from the leftovers.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information