MongoDB Connector for BI 2.14.4 with Power BI return null value when the field is array object

My Power BI can successfully connect to MongoDB through MongoDB Connector for BI 2.14.4.
But when the field in the collection is an array object, the value show in power BI is NULL ,so can’t load the data to analyze.

I don’t know the reason. Could anyone help me to find out where the problem is coming from?