The bug report linked by @MichaelWimma-RWProfiles covers the case of MSFS
2020 packages compatibility.
In your case, this is a native MSFS 2024 project, right?
If so, the dirt on parking spot cannot be disabled yet in SU1, but a “Draw Dirt” checkbox has been added to TaxiwayParking object properties and will be available with SU2.