The bug

Lodestone compasses do not take your sub-block position into account when determining the point direction. This makes them slightly inaccurate at short ranges.

How to reproduce

Stand on the block next to a lodestone, and use a compass on it. Stand as close to the lodestone as you can, and sneak from side to side, but remain within the 1x1 block space. Keep your camera still. Notice the angle of the compass does not change at all.

Now take one small step into a neighboring block. Instantly, the compass will sharply change to a near-45 degree angle, even though your actual angle to the center of the lodestone barely changed.

Expected behavior:

Actual behavior:

Notes

Java Edition does not have this bug.