Mohave 10.14.3 and Acrobat DC fillable document saving problem-
If I get a fillable form from IRS or other government site that needs to be filled in, I can save it to my computer one time. But if I reopen the document to add other information to a fillable area, I cannot save the document a second time. I get an error message saying the file contains "a number that is out of range". This happens for documents from many different websites, so I think the error comes when the document is saved using Mohave. Once saved the "producer" under the document properties is QuartzPDF Context. Something must be incompatible there.
Thank you for reporting the issue.
Please check that the form is not being opened in Apple Preview, it happens to get corrupted. Try downloading again from IRS website and instead use Adobe Acrobat/Adobe Reader.
1. Please share the test file with us using https://forums.adobe.com/docs/DOC-7161 and
2 the version of Acrobat installed on your machine for us to investigate furthur.