I am making icons in Illustrator.
- Created a 1000px x 1000px file.
- Set horizontal & vertical guides at midpoints - 500px, so the intersection is accurate centre of the document.
- Using the pen tool, I hover to get the smart guide to snap to guide. BUT!!!! It snaps at position 500.5px not 500.0p.x Both horizontal & vertical are affected.

The picture shows the "smart guides" assisting at the wrong point. The cursor vanished for the screenshot, but is hovering on "intersect".

I reset Illustrator settings & started a new file with no other items. Illustrator V 24.3. Mac OS 10.15.6.