Attach (recommended) or Link to PDF file

N/A

Web browser and its version

Firefox 140.0.4

Operating system and its version

Arch Linux

PDF.js version

5.3.93

Is the bug present in the latest PDF.js version?

Yes

Is a browser extension

No

Steps to reproduce the problem

1. Open http://54.193.163.58:8877/ae9ca6e62123620/output.txt (bot logs from PR [Editor] Only add a popup to an existing annotation if it exits #20104).
2. Notice the following failure in the stamp integration test:

2) Stamp Editor Basic operations must load a PNG which is bigger than a page
  Message:
�[31m    Expected '' to equal 'Image added'.�[0m
  Stack:
        at <Jasmine>
        at file:///C:/pdfjs/botio-files-pdfjs/private/ae9ca6e62123620/test/integration/stamp_editor_spec.mjs:129:25
        at async Promise.all (index 0)
        at async UserContext.<anonymous> (file:///C:/pdfjs/botio-files-pdfjs/private/ae9ca6e62123620/test/integration/stamp_editor_spec.mjs:116:7)

What is the expected behavior?

The test should pass consistently.

What went wrong?

The test fails intermittently.

Link to a viewer

No response

Additional context

The intermittently failing assertion in this test was introduced in #20055 and was introduced in four other editor tests too. It's possible to easily reproduce this locally by introducing a delay here which makes the test permafail: