select inside "do as database" seems not to work with "let me := this" - or am I doing it wrong?

 Hi out there,

I'm trying to get a script running (ninox 3.12.8 docker), links between the current table and "Bilderdatenbank" do exist:

let me := this;
let bilderEmbed := [{}][false];
let dummyBilder := do as database Bilderdatenbank
        let mangelBilder := (select Bilder where Mangel = me);
        let helperArray := [{}][false];
        for bild in mangelBilder do
            let embedJson := [{
                        Bild: {
                            _type: "imageBase64",
                            format: "image/jpeg",
                            width: 200,
                            height: 200,
                            source: loadFileAsBase64(bild.Bild)
                        }
                    }];
            helperArray := array(helperArray, embedJson)
        end;
        helperArray
    end;
bilderEmbed := array(bilderEmbed, dummyBilder);

"me" is a record with Nr 186. The database "Bilderdatenbank" just holds a table "Bilder". The variable "mangelBilder" is always empty. If I modify line 4 like this, it works fine:

let mangelBilder := (select Bilder where Mangel = 186);

Could someone please point me in the right direction?

Thanks in advance!