Searching library gives different results with Mac and Windows

This is a bit strange. A testing library with 17 references, all having PDFs.

Selecting “search whole library” and selecting author, year, journal, etc. gives the same results on a Windows machine and a Mac.

However, choosing “PDF” or “any field + PDF with notes” will show a different number of found records on each platform.

e.g. searching for “redshift” (without quotes) will find 5 references on the Mac and 8 on Windows. Searching for “qso” finds 1 on the Mac and 2 on Windows. Windows will always find more.  I’ve checked the “extra” references found by Windows and they do have the term within the PDF.

All of the PDFs are OCR’d and are searchable. Opening them in Acrobat allows the term to be found easily.

I had the two laptops side-by-side to make sure that the same thing was being done on both, and had someone else check to make sure I wasn’t seeing things or doing something silly (sadly possible).

Anyone else had something similar? I’ve searched the forums but could have missed something obvious

(The libraries are synced, and the machines have been restarted.)