If you use an interface as type within an external function in a contract for which you output -f interface, it will use the full path. Example (see #4294 (comment)):

def distribute_token(token: .../snekmate/venv/Lib/site-packages/vyper/builtins/interfaces/IERC20.vyi, data: Batch):

There should be no path within an interface output IMHO, but simply the interface type:

def distribute_token(token: IERC20, data: Batch):