Do not set contiSuccUpdate to zero when cost is NaN

Seq2SeqSharp/Tools/BaseSeq2SeqFramework.cs

@@ -485,7 +485,7 @@ internal void TrainOneEpoch(int ep, ICorpus<IPairBatch> trainCorpus, ICorpus<IPa
                                     throw new WeightsCorruptedException($"The weights has been corrupted. Abort training and please check checkpoint files.");
                                 }
 
-                                contiSuccUpdate = 0;
+                                //contiSuccUpdate = 0;
                                 break;
                             }