formal dawn
Sometimes the customer requests, that you can Instantly fill, open twice.
E.g. you sell a sword and right afterwards the exact same request of this person opens again (so they buy it twice.... Confused people i guess😜)
It happened to me in the vale-blacksmith, that I own. 
so it Happens quite frequently. Not everytime but i guess the rate is at around 10-30% for me that this bug appears.
Hope it helps!
Not a bad bug, but it should be solved one day anyway ☺️
earnest tundra
Sounds like its good for business at least 😉 Thanks for your report.
Would you mind sending your save file so that we can check it out please? You can paste here, DM to me or email to [email protected]. If mailing, please include a link to this page or include your username. There is no personal or hardware information included. Right-click the game in Steam Library, choose Properties, Local Files, Browse, saves, autosave.xml.