Unhandled CitationMetadata format

I am using firebase_vertexai: ^0.1.1. in Flutter App.

Example Request:
var response = await model.generateContent([Content.text(prompt)]);

Sometimes I am getting error this error:

FormatException: Unhandled CitationMetadata format<…>
#0   _parseCitationMetadata (package:google_generative_ai/src/api.dart:729:10)<…>
#1   _parseCandidate (package:google_generative_ai/src/api.dart:645:9)<…>
#2   MappedListIterable.elementAt (dart:_internal/iterable.dart:425:31)<…>
#3   ListIterator.moveNext (dart:_internal/iterable.dart:354:26)<…>
#4   new _GrowableList._ofEfficientLengthIterable (dart:core-patch/growable_array.dart:189:27)<…>
#5   new _GrowableList.of (dart:core-patch/growable_array.dart:150:28)<…>
#6   new List.of (dart:core-patch/array_patch.dart:39:18)<…>
#7   ListIterable.toList (dart:_internal/iterable.dart:224:7)<…>

Any idea or suggestion?