Column with IF condition in PowerQuery

Hello, everyone,
I cannot solve this little problem with creating a custom column in PowerQuery.
In this PBIX file file I have a simple table with three columns:
- supplier code
- activity
- level
I want to create a fourth column Check: if Level is null, Check = ❌ otherwise ✅
But, as you see in the file here, the entire column is populated with ✅. Even trying to create a simple calculated column does not work: only ❌ values appear.

is this a problem with special characters?
Thanks to those who can help me.