Can not create any file named 'Con' regardless of case and extension

Steps to reproduce

1. Add New… -> New file…
2. Choose whatever template like QtQuick or Empty file
3. When asked to name the file, start typing with "con".

Expected result

Nothing unusual, just accept the name as it is.

Actual result

Text in the text filed is highlighted in red, Next button is disabled, as if "con" is not a valid filename. If you add an extension manually, e.g. "con.js", "con.qml" or any other — it would still be considered an invalid filename.

Additional information

You can always rename files afterwards, which compiles and works fine.

How do I even find it? I wanted to create a component named "Content.qml", but noticed a red text half way through the input.