Hope you are doing well. Sorry for your experience with Adobe Scan.
Do you experience this with every file you are trying to delete? I would like to know more about the file. Is the file visible here: https://acrobat.adobe.com/link/documents/ in the Scan folder?
If yes, the file should delete normally. If not, you might want to check your internal storage to locate and delete the file manually.
Look forward to hearing from you.