DOES NOT CONTAIN search filter not working for MULTIPICKLIST

Hi

The DOES NOT CONTAIN search filter does NOT work for MultiPicklist values.

The CONTAINS condition works OK to find a value within a MultiPicklist, but when I just change this to DOES NOT CONTAIN then the condition does not work properly and returns zero results.

I have looked for the bug in the code, but unfortunately haven't found it.

Any idea where to find and fix this please!