I’ve been having the same issue as the Calibadger5544 and KasparsKursiss. I noticed it a couple of days ago. I’m a Cross stitcher and most of my patterns are in PDF format. I use Acrobat to highlight stitches in the pattern so I can keep up with where I am. Along with the answers to the the questions below, I wanted to add that if my IPad sits idle for awhile this same thing happens. My device goes to sleep after 10 minutes, so there have been times, before then, that I tried to highlight on the document and tap Save only to be met with the create local document pop up. I have to close the app and reopen it every time to be able to continue and always lose the previous highlights I made. Q1: What is the iOS version? (Go to Settings > General > About > Version.) 11.2.2 Q2: What is the Acrobat Reader version? (Go to Settings > Adobe Acrobat > Version.) 18.01.15 (180932) Q3: Does the problem happen to "Local" PDF documents and/or the documents stored in cloud storage (e.g. iCloud Drive, Dropbox, Google Drive)? Local documents. I haven’t tried cloud storage. Q4: What is the typical file size of the PDF documents that exhibit the problem? Typical size is 2 to 3 megs Q5: How do you open your PDF document? Do you open it from the "Local" or "Recent" file browser in Acrobat or some other app (e.g. the iOS 11 Files app)? I always open from Local Q6: Does the problem happen to all of your PDF documents all the time (100% of the time)? 100% Q7: How do you close the PDF document with pending changes? Do you tap the < (Back) button or do something else? After I tap Save, then I tap the back button. Q8: Do you always see the "Document saved" toast message when you close the PDF document? Sometimes I see the toast message after I tap Save, others I see it when I close the document. Q9: If it's all possible, would you please describe what you do step-by-step? I added one more step to the example you gave but I do this every time. Launch Acrobat. Go to My Documents > "Local". Open a PDF document under "Local". Add Highlight annotations. Tap the Save button to save highlights. Tap the < (Back) button to go back to My Documents. Did you see the "Read-Only Document" alert after you (a) switched back to Acrobat from other apps or (b) woke up your device from sleep? It happens both when I switch apps and also when wake my IPad up from sleep.
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