Currently while passing Buffers and UInt8Arrays over json-rpc changes the type into an object as mentioned bellow
For Buffers
{ type: "Buffer", data: [120, 32, 45] }
or For Uint8Arrays
{"0": 120, "1": 32, "2": 45}
This causes an issues when sending a zomeCall that expects a HoloHash/Uint8Array: #73