I am out of ideas and hopefully you will direct me in the right direction.
As a manually trigger a single 'Email' input field named 'Employee' was chosen. The selected Sharepoint list contains a column of the same name, but it is of type 'Person' (so a lookup). I already ensured, that I got the right column name (via the list settings) and as the tooltip in the condition indicates (see figure) imo I think got the right fieldname. So the access for a filter query should be 'Employee/Email' - at least to my knowledge. However, the return value of Get Items is empty, while I was expecting to find a list of entries with information from the Sharepoint list.

Two additional notes:
1) Without any filter I actually can trigger the condition after and select only the entries I am looking for, but my intention is to rely on the filter only.
2) If I am using 'Employee/ID' and replace the dynamic input with a hardcoded number ... the flow works.
What do I miss here? Any hint is much appreciated!