Formulas corrupted when saved and re-opened on Mac

I asked about this when it happened before. Nobody had an answer.

I saved a document with formulas. I continued to edit and tried to do another save. A box appeared telling me “another user” had modified my document. There is no other user unless there is very strange malware in my Mac that does nothing I have seen but corrupt formulas in Libre Office documents. Formulas are moved from place to place, inserted in strange places, enlarged, and shrunk. Using a Mac with OS10.11

If I were allowed to attach PDFs, I could show you.

You can upload any file at a free file hosting sire, like which doesn’t require people to register Iin order to download a file, then post the link here.

It would help to see a source ODT in addition to PDF. You could also stick them on Google Drive to share, so there are other options. But I think you can attach them to questions (and see the advice about how to make this work for PDFs as well.).