stamp-self causes subsequent pen lines to appear in the wrong location

[rigdern]

Repro steps

I reproed this with Boxer 3.4.19 2024-06-24

1. Download, unzip, and open stamp-self and pen lines repro.box.zip
2. Run the first code box labeled repros-bug

Expected result: The pen lines originate from the middle of the graphics box:

Actual result: The pen lines originate from the top-left corner of the graphics box:

Here's a screenshot of the example that repros the issue: