Why does Google Maps mislead you more here than at home?
The short answer
Google Maps assumes grid-based, car-navigable streets. The medina has none. GPS bounces off high walls with ten-to-thirty-metre errors. In a city where parallel streets are five metres apart, that puts you on the wrong street.
The medina is a three-dimensional network where streets pass under buildings, split into levels, and sometimes exist as passages through private homes that are open during the day and locked at night.
Google's data depends on Street View cars and user contributions. Street View cars cannot enter streets narrower than their wheelbase — which excludes most of the medina. Entire passages are missing. Others are marked as through-streets but have been bricked shut for years.
Locals navigate by landmarks. The fountain, the bakery smell, the tree growing through the wall. "Go toward the smell of bread, turn left at the mosque, ask again." This system has worked for a thousand years.