mypy error after upgrading PySide6 to version 6.6.3

Our CI is failing on the following file after installing version 6.6.3 of PySide6. We had no error with 6.6.2:

/usr/local/lib/python3.9/site-packages/PySide6/QtCore.pyi:5858: error: invalid syntax [syntax]

What is odd is that another project is failing on the following:

/usr/local/lib/python3.9/site-packages/PySide6/QtGui.pyi:1050: error: invalid syntax [syntax]

It seems to do with the # type: syntax in those rows.

We need a fix asap as this is blocking us from upgrading to the latest version of PySide6, which we need to get other bugfix into our users hands.