Gen2 Dataflow load to Lakehouse error - Can't insert null data into non-nullable column

I am trying to load a handful of tables from Business Central to a Fabric Lakehouse using Gen2 Dataflows and the BC connector but keep getting the following error. For reference, I have the dataflow set to create the table and replace any existing data.

104100 Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: DataFormat.Error: Error in replacing table's content with new data in a version: #{0}., InnerException: We can't insert null data into a non-nullable column., Underlying error: We can't insert null data into a non-nullable column. Details: Reason = DataFormat.Error;Message = We can't insert null data into a non-nullable column.;Message.Format = We can't insert null data into a non-nullable column.;Microsoft.Data.Mashup.Error.Context = User

I understand what the error message is saying but am confused about why the columns created by the dataflow are not nullable by default. Is there a way to specify the columns to be nullable? I'd like to avoid manually creating the tables in a notebook as some can be hundreds of columns long.