Pycharm is generating language errors for Python version 3.6 although interpreter is 3.9

Question

The language interpreter is set to a Python 3.9 version:

But a Python scratch file is being parsed by some kind of 3.6 interpreter:

Note that I created in two different scratch files and the same error occurs. Why would this happen and is there a workaround [short of creating an entirely new project from scratch]?

I am on Pycharm Professional 2021.3.1

Update based on answer by @TurePaisson he though maybe the Code is compatible with specific Python were set. That was a shrewd guess - but turns out I have not set that:

Update The following snippet can be used to test python3.6 vs 3.8+

x = (y := 3) + 7 

Answer 1

In the preferences dialog, search for "versions" and you will find, under Editor/Inspections, an inspection "Code is compatible with specific Python versions" with checkboxes for which versions to check against.