Created attachment 157877 [details]
Usage Log

SUMMARY
Created assistants snap to the wrong center lines for the document.

STEPS TO REPRODUCE
Open a new file. A smaller file might make the effect easier to measure the pixels, but the effect occurs for any file size.

Create a new assistant. It is most easily obvious with rulers and ellipses, but it happens for any assistant.

Drag it around! You'll notice the assistants snap to the "center" lines of the document. Except, they are not. These center lines are off from the real document center, and as you pan and zoom around the canvas, the snapping positions will change.

Turning off View > Snap to > Image center disables the snapping of the assistants.