We have stepped through releases and found that this was introduced in 3.7.7, the issue was not present in 3.7.6. Both of the "steps to reproduce" workflows described above are triggering the bug in 3.7.7.

"editing" and saving a prefix multiple times in the UI (not actually editing anything, let alone the read-only JSON field) results in the field value being escaped multiple times:

We have written a script that finds and repairs the affected data, which can be found at https://github.com/FliesLikeABrick/netbox_fix_json

Thanks for reporting this problem and for providing clear and comprehensive steps to reproduce. I was able to reproduce the option-1 case exactly as described in a fresh 4.0.5 install. The option-2 case reproduces slightly differently from how it's written up in the issue body (the value { "thing1": "value1" } gets escaped and displays as "\"{\\\"thing1\\\": \\\"value1\\\"}\""), but I see your follow-on comment lines up with that. I suggest editing your issue body to match what you (and I) actually see in option 2, but in any case I'm moving your issue out of triage.

Extra thanks for doing the additional archaeology to determine where the problem seems to have been introduced. That's potentially a big help.

Huh, my option2 text was actually correct but github or markdown was eating the backslashes . I have edited it to be closer to what is being observed but my escaping may not 100% match the values seen in a reproduction (especially depending on whether someone is observing the raw database value vs that returned in the UI vs that returned by the API before or after being decoded as JSON)

Hi all, I am the reported of the original issue. This PR appears to fix the issue for null values only. Editing existing values, or creating a prefix with a default value both lead to escaped strings being placed in the field