TYPO3 Core

Hey,

I'm using the following TCA configuration to get a mm-relation:

        // ...
        "rental_fees" => [
            "exclude" => true,
            "label" => "LLL:EXT:my_portal/Resources/Private/Language/locallang_db.xlf:tx_portal_domain_model_flat.rental_fees",
            "config" => [
                "type" => "select",
                "renderType" => "selectMultipleSideBySide",
                "foreign_table" => "tx_portal_domain_model_rentalfee",
                "foreign_table_where" => "AND {#tx_portal_domain_model_rentalfee}.{#pid} = ###CURRENT_PID### AND {#tx_portal_domain_model_rentalfee}.{#hidden} = 0 ORDER BY tx_portal_domain_model_rentalfee.startdate",
                "size" => 5,
                "MM" => "tx_portal_flat_rentalfee_mm",
                "maxitems" => 1,
                "minitems" => 1,
                "fieldControl" => [
                    "addRecord" => [
                        "disabled" => false,
                        "renderType" => "addRecord",
                        "options" => [
                            "title" => "Neuen Datensatz hinzufügen",
                            "setValue" => "append",
                            "pid" => "###CURRENT_PID###" 
                        ],
                    ],
                ]
            ],
        ],
        // ...

Everything is working fine on already saved "flats", but If I add a new one and want to add my rentalfee first, the "new to save" rentalfee isn't added to the ###CURRENT_PID###.

When checking the developer tools, it's definitely set (check the attached screenshot for information).

Thanks for reading, have a nice day.
- Julian