While there are a myriad of problems faced by Historians, knowledge can still be produced.
I agree that when Historians study historical knowledge, they will encounter a range of problems. These could include being exposed to contrasting opinions and having to decide which is correct, dealing with exaggeration due to people retelling events with emotion, lack of sources, too many sources, dealing with the popular belief and dealing with their own western perspective. To determine the validity of these claims, I believe it is important to consider a range of characteristics, including: how specific it is, how objective it is and whether or not it is time bound. This will help the Historian to identify whether the source is valuable or not.
To neutralize or mitigate these threats to knowledge, the historian can consider a range of sources and avoid assumptions. Most importantly, I feel that a historian should identify the nature of the knowledge claim when they extract knowledge from a source, this way, when they publish their research, readers will be aware of the potential biases. For example, if the historical knowledge was extracted from a judgement statement, then the reader will then be able to take the information with a grain of salt.