If you create a filled rounded rectangle with a 1 pt border, add it to the Asset Export panel and export, the end result is noticeably clipped. Even though the shape may be aligned to be pixel perfect and the stroke aligned so that it should be inside, the output shows the frame is now non uniform in terms of stroke width.

If you didn't use stroke, you probably won't notice the inaccuracy.

See the attached image and the edges are clearly truncated.

Says there are some fundamental alignment issues that need to be addressed.