Using BCD as filter in RatePlanCharge query will return Unknown error
Issue: Using SOAP API, run a query against RatePlanCharge object and add BillCycleDay=[integer] as filter. This will result to Unknown_error.
Using BillCycleDay=Null or BillCycleDay:=Null will return success results, as well as create Export call.
Reference Number: PROD-1248/BIL-15444
Status: Zuora Engineering team is working on it.