Hi Stefanie! Thank you for reporting this and for sharing the screenshots earlier! We're currently looking into your case with our QA team. So far we've only seen a small number of similar reports over the past year, each caused by different edge cases, which makes this issue a bit tricky to reproduce.

If you're open to it, a few additional details could help us understand what might be happening:
1. Do you know how this PDF was originally created? (for example from MS Word, Adobe Acrobat, InDesign, or another PDF editor)
2. Could you share the original file and the file you uploaded and edited in pdf.net where the fields were not saved?
3. Is there a chance the same document was opened at the same time in multiple tabs, browsers, or devices?
4. If possible, would you be open to recording a short screencast while reproducing the issue? Tools like Loom or ScreenPal (both have free versions) would work great.

In the meantime, there are a couple of actions that normally trigger saving changes in the editor, besides switching to another tool (which you already tried):
• Clicking the arrow in the top-left corner “Back to my documents” to return to the dashboard
• Downloading the file
If you have a moment to try that and let us know whether the added fields and changes stay in the document after these actions, it would help us narrow things down.

Thanks again for taking the time to report this! We really appreciate it and want to get to the bottom of what’s happening.