The exact scenario happened to me years ago when PDFPenPro was new. I tried it out, all looked good, at about page 11 (as I recall) of a corporate tax return, I watched as everything I had added to the form appeared (quite literally) to just slide off the screen much as decals that were too wet would slide off the models I built as a kid.Just a word of warning to others: I purchased PDFpen from Apple's Mac App Store after trying a demo, because I had a business-critical IRS form I had to fill out, and Apple Preview couldn't do the job. Unfortunately, PDFpen was a disaster, failing to even save changes/files correctly. I tried to get a refund from Apple's Mac App Store, but Apple refused to refund the purchase (which makes me extremely wary of buying any software again from Apple).
The folks at PDFPen (Smile) refunded my purchase and, as a bonus, let me keep a license for their software. Not that I ever used it again. What bothered me most in my conversation with them was my belief they knew of the problem. Why, then, didn't they advise against using their software for the common-enough purpose of filling in forms created with Adobe's Acrobat?
One comment I recall. Preview had (and still has) the same issue, and I believe PDFPen was using (and is probably still using) whatever "engine" is built into macOS to power Preview's handling of PDFs.
We've had several versions of Acrobat Pro at work. I've used it to create our own forms that we posted online that would then auto-generate emails to us with just the tiny amount of data which users added as they completed the forms. That data auto-filled the same forms in our office, which were then completed PDFs ready for review. Slick, but as Acrobat was a moving target, becoming ever more expensive with new versions, it was not cost effective to continue.
Had not heard of LiveCycle Designer. Read about it. Seems a way for Adobe to extend the PDF format it created but didn't try to control.The problem with the tax form does appear to be the IRS using Adobe LiveCycle Designer to create their PDF
Found this related document, which is, ironically a PDF:
Middle Georgia State University said: