There are 2 functions calculating APY: one calculates borrow APY, one lending APY. So, generally both should yield similar results, that is lending APY - protocol fees ~= borrowing APY. However, lending APY includes utilization rate of the pool and APY is adjusted over it, while borrowing APY doesnt account for it, leading to borrowing APY assuming utilization rate is always 100%.
and lendingRate() function: 
In comparison, borrow APY is calculated as follows:
So borrow APY doesnt account for utilization rate as lending APY. So it shows that youll have to pay high fees for borrowing, and youll get proportionally less for providing value to the protocol.
There is actually yet another function, combining the two above, overallNetAPY(), which calculates both lending and borrowing APY, and returns the value combined.
Both functions are not used by the protocol, but it might false information to either offchain clients or external protocols integrating with WiseLending.
Additional thing to consider is that Pendle markets can be only added; there is no function to remove them.
