Step 7 from https://drafts.csswg.org/resize-observer/#create-and-populate-a-resizeobserverentry says:

If target is not an SVG element ... do these steps:

1. Set this.contentRect.top to target.padding top.
2. Set this.contentRect.left to target.padding left.

Our implementation is missing that logic.