Odata response contains bad metadata seee [1]:
URL: http://localhost:8080/odata4/olingo_basic/Source/Customers(1)/Orders_FK0(1)
Actual metadata: $metadata#Orders/$entity
Expected metadata: $metadata#Customer(1)/Orders/$entity

URL: http://localhost:8080/odata4/olingo_basic/Source/Customers(1)/Orders_FK0
Actual metadata: $metadata#Orders/$entity
Expected metadata: $metadata#Customer(1)/Orders

[1] http://docs.oasis-open.org/odata/odata/v4.0/errata02/os/complete/part1-protocol/odata-v4.0-errata02-os-part1-protocol-complete.html#_Toc406398268