In this document it says "According to IEC 60601-1, the leakage current limits are provided in Table 1."
If the leakage current is due to Y capacitor, the load R and the the parasitic capacitance of the PSU transformer will form an RC divider.
But then the leakage current depends on the load. If the load is big the stray voltage will be big and the leakage current will be small. If the load is small(low impedance setting), then the voltage will be small but the current will be higher comparing to high load impedance.
For which load the leakage current is measured and presented in datasheets?