We didn't have the subscription, and there was no option to upload documents, or any information in the app preferences as to what was happening at all.
So, we couldn't find any information why it was happening, except after our complain and an update later, the background service started closing files when the Adobe app was exited.
We had tens of thousands of applicant documents, most of them contained personally identifiable information (PII) about future students, those files should not be even stored locally, except for the protected PII storage, yet along being uploaded to a random S3 bucket somewhere to be stolen by hackers.
If you're using Windows and have Adobe installed, just check your running programs and on top you'll see that weird Adobe service that you cannot disable even if you turn off its auto-start feature. Acrobat reader is supposed to be a PDF viewer, why does it even have a background service for f.ck sake.
