I tried this, and in Archicad 24, if you schedule Slabs, the "Related Zone Name" and "Related Zone Number" schedule fields correctly return the info about the Zone the Slab is located in.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac27