macOS: HTML input type number triggered twice when clicking the arrows (Catalina 10.15)

When using the QtWebEngineView with a <input type="number" step="1">, the arrows that appear when hovering the control are triggered twice when got clicked. This seems to only happen on macOS 10.15 Catalina.

A quick way to reproduce it is, using the simplebrowser example (https://doc.qt.io/qt-5/qtwebengine-webenginewidgets-simplebrowser-example.html) and opening a page with an input number.

Clicking the arrow should increase the value of the field one by one, but with the QtWebEngineView on macOS 10.15 it gets increased two by two.

I have created two online pages to reproduce it. One is a very minimal with almost no HTML rather than the field itself, and a codepen:

https://sinspiral.com/qtbug/simple-input-number.html
https://codepen.io/sinspiral/pen/LYYOxOm

Steps:

1. Open the simplebrowser example.
2. Use one of the urls above (https://sinspiral.com/qtbug/simple-input-number.html)
3. Hover the input field
4. Click the small arrow up once.

Result:
The input value increases from 0 to 2 with a single click.

Expected:
The input value to increase just 1 with a single click.

Environment:
I'm able to replicate with a QtWebEngineView on 5.9.3 and 5.13.1, but only using macOS 10.15. On previous macOS 10.14 and lower seems to work fine.