diff --git a/src/Microsoft.OData.Core/ODataCollectionReaderCore.cs b/src/Microsoft.OData.Core/ODataCollectionReaderCore.cs
index 2052f60cd2..14fec8660b 100644
--- a/src/Microsoft.OData.Core/ODataCollectionReaderCore.cs
+++ b/src/Microsoft.OData.Core/ODataCollectionReaderCore.cs
@@ -208,11 +208,6 @@ protected bool ReadImplementation()
                     result = this.ReadAtCollectionEndImplementation();
                     break;
 
-                case ODataCollectionReaderState.Exception:    // fall through
-                case ODataCollectionReaderState.Completed:
-                    Debug.Assert(false, "This case should have been caught earlier.");
-                    throw new ODataException(Strings.General_InternalError(InternalErrorCodes.ODataCollectionReaderCore_ReadImplementation));
-
                 default:
                     Debug.Assert(false, "Unsupported collection reader state " + this.State + " detected.");
                     throw new ODataException(Strings.General_InternalError(InternalErrorCodes.ODataCollectionReaderCore_ReadImplementation));
diff --git a/src/Microsoft.OData.Core/ODataCollectionReaderCoreAsync.cs b/src/Microsoft.OData.Core/ODataCollectionReaderCoreAsync.cs
index 79703d1982..1ef09e1d1f 100644
--- a/src/Microsoft.OData.Core/ODataCollectionReaderCoreAsync.cs
+++ b/src/Microsoft.OData.Core/ODataCollectionReaderCoreAsync.cs
@@ -86,11 +86,6 @@ protected override Task<bool> ReadAsynchronously()
                 case ODataCollectionReaderState.CollectionEnd:
                     return this.ReadAtCollectionEndImplementationAsync();
 
-                case ODataCollectionReaderState.Exception:    // fall through
-                case ODataCollectionReaderState.Completed:
-                    Debug.Assert(false, "This case should have been caught earlier.");
-                    return TaskUtils.GetFaultedTask<bool>(new ODataException(Strings.General_InternalError(InternalErrorCodes.ODataCollectionReaderCoreAsync_ReadAsynchronously)));
-
                 default:
                     Debug.Assert(false, "Unsupported collection reader state " + this.State + " detected.");
                     return TaskUtils.GetFaultedTask<bool>(new ODataException(Strings.General_InternalError(InternalErrorCodes.ODataCollectionReaderCoreAsync_ReadAsynchronously)));