This happens when Snap to Grid is enabled. Even when invisible, it still affects snapping and prevents Smart Guides from assisting to snapping at artboard’s edges.
Great to hear that! Thank you for replying back. I am marking it as Resolved. If something else strange happens — please comment.
Can you please share the test file with these guides you created within only?
Also, what are you snap settings? Do you have Smart Guides enabled, and Snap to Grid disabled? Even if you don’t show the grid, the enabled Snap to Grid option will force guides to stick to invisible grid intersections.