During this COVID-19 crisis, I finally upgraded my desktop machine to Windows 10 (1903 Build 18362.720). I downloaded the latest Adobe Digital Editions to read some ePUB books from my local library which like many uses an Overdrive server to deliver .ascm files for the book. After 'browing' several ePUB books and downloading the associated .ascm files I tried to run the files to have ADE 'fulfill' the request. Every single book threw the E_ADEPT_DOCUMENT_TOO_SHORT error. I had never seen this error before in my several years of 'borrowing' ePUB books from my local library so I went back to my old laptop which is still running Win 7 SP2. Did a 'return' on the books I had 'borrowed' and rechecked them out with new .ascm file downloaded to the laptop. I then updated the laptop to the same version of ADE (4.5.11) and ran those same .ascm book files. All the books were 'Fulfilled' successfully by ADE and appeared in my default library view in ADE.
This says to me that there is definitely something really, really broken with Adobe's latest builds of ADE running under Windows 10.