Codex Desktop macOS: pet expand button renders a black offset circular layer

What version of the Codex App are you using (From “About Codex” dialog)?

Codex Desktop 26.715.31925 (build 5551).

What subscription do you have?

ChatGPT account in Codex Desktop.

What platform is your computer?

macOS 27.0 (Build 26A5378n), Apple Silicon.

What issue are you seeing?

When a custom desktop pet is visible, its circular expand/activity button (the light-gray circle showing 1) is rendered with a large opaque black crescent along the lower-left edge.

The artifact is not normal antialiasing or a shadow. It looks like a second dark circular layer behind the button that is offset relative to the gray foreground circle.

What steps can reproduce the bug?

1. Enable a custom Codex desktop pet.
2. Show the pet so that the circular expand/activity button with 1 appears next to it.
3. Observe the button: an opaque black crescent is visible behind the lower-left portion of the gray circle.
4. Toggle the pet off/on and restart Codex; the artifact remains.

What is the expected behavior?

The expand/activity button should be a single clean gray circle, with no opaque black layer or crescent visible around it.

Additional information

I validated the installed custom-pet package to rule out a sprite asset issue:

• spritesheet.webp is a valid RGBA v2 atlas (1536x2288, 8 columns x 11 rows).
• The atlas validation passed with no errors or warnings.
• No opaque chroma-key pixels, chroma fringe, or transparent-RGB residue were reported.
• The idle animation frames contain only the character; they do not contain a circular black component.

This appears to be a Codex Desktop overlay/button compositing, masking, clipping, or positioning issue rather than a custom-pet asset issue.

Screenshot description: the black layer forms a hard-edged crescent from the left side around the bottom of the gray 1 circle.