CONTAINSSTRING not working

Hi there,

I am using containsstring to check the spelling of my sales managers... 😉
I am using containsstring to filter valid entries and create a link to the spelling error. I call it the Wall of Shame.
However, when I have additional words in the field, it does not work. Long story short:

as you can see "kein interesse" should result in a blank, but lines 5 and 6 of the lower table has a result. I have narrowed it down to everything that has
a) a special character and

b) inbound in front.

My understanding of CONTAINSSTRING is that it should find the string. What am I doing wrong?

Thanks y'all

Marko