mocked onClick changing the contents of it's event

[sterlingwalsh]

Describe the bug

In an onclick event the currentTarget value is being altered (removed). Reproduction in codesandbox below. Extracting the event from the mocked implementation of the function itself has a value for the currentTarget property. In the mock.calls or mock.lastCall property on the mock itself, however, the currentTarget value has been removed. It is being changed within the reference of the event itself somehow as can be seen by both the expect().isEqual and expect().toBe tests.

Expected behavior: event remains consistent.

Reproduction

https://codesandbox.io/p/devbox/lingering-sunset-7m8gzm?file=%2Fsrc%2Fitem.test.tsx%3A26%2C44

System Info

System:
    OS: Linux 6.1 Ubuntu 20.04.6 LTS (Focal Fossa)
    CPU: (2) x64 AMD EPYC
    Memory: 1.78 GB / 4.14 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 20.12.1 - /home/codespace/nvm/current/bin/node
    Yarn: 1.22.19 - /usr/bin/yarn
    npm: 10.5.0 - /home/codespace/nvm/current/bin/npm
    pnpm: 8.15.6 - /home/codespace/nvm/current/bin/pnpm
  npmPackages:
    @vitejs/plugin-react: ^2.0.0 => 2.0.0 
    vite: ^3.0.0 => 3.0.0 
    vitest: ^0.21.1 => 0.21.1

Used Package Manager

npm

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[hi-ogawa]

npmPackages:
@vitejs/plugin-react: ^2.0.0 => 2.0.0
vite: ^3.0.0 => 3.0.0
vitest: ^0.21.1 => 0.21.1

The dependencies are quite old. Can you test with the latest version Vite 6 + Vitest 3?

[github-actions]

Hello @sterlingwalsh. Please provide a minimal reproduction using a GitHub repository or StackBlitz (you can also use examples). Issues marked with needs reproduction will be closed if they have no activity within 3 days.