The same thing is happening to me. When I revisited the other store, my ads appeared as their listings.
Summary of the issue
Other store’s ads appearing as my own. Mine appeared under their store.
Expected results
My ads should always appear under my store and only my store. Others’ should always appear under their own store and only their own store.
Actual results
Visited another store, then visited my store. Their listings appeared under my store. My listings were gone. Returned to the other store and my listings appeared there as theirs. This is reverting back to the correct listings after a few minutes but visiting a different store results in the same switched listings occurring again.