Why a correct PDF can still miss the cuts
A PDF records physical page and drawing coordinates. The print dialog may still scale that page to a different paper size or to the printer's printable area. Even a small scale change can make labels near the bottom or right edge miss their cut lines.
Before printing, confirm three matching settings: the stock's paper size, the PDF's selected page size, and the printer tray. Select Actual Size or 100%, then disable Fit to Page, Shrink, or automatic scaling. The exact control names vary by viewer and printer driver.
Test scale separately from position
The calibration PDF has a 100 mm line. Measure it after a plain-paper print. A short line indicates scaling; a correctly sized line in the wrong position indicates an offset. Correct the cause you measured. Enlarging a label size to compensate for driver scaling will usually create new errors elsewhere on the page.
If you switch between browsers, PDF viewers, or printers, repeat the plain-paper test. Keep the successful settings with your label stock details so the next batch starts from known measurements.