Access append query multiplying results to SharePoint

Question

I have an Access 2010 query that uses two left joins between two tables (SQL below, both tables are linked SharePoint 2010 lists). When I run it as a Select query it produces 3,701 results - the correct number. When I run it as a Make Table it does the same. When I run it as an Append query to an Access table it also runs correctly. However, when I try to append the results to a linked SharePoint 2010 list it appears to multiply the results to the point I'm getting over 70,000 records in the list. Any idea why this would happen?

INSERT INTO [EMT-Function Alignment] ( [Business Group], [Business Unit], Division, 
  [Corp ID], Associate, Plan, [Process ID], Process, City, Address, RTO, Rating, FTE, Team, 
  Site )
SELECT BIA.Company, BIA.[Business Unit], BIA.Division, 
  [Event Management Team Contact Info].[Corp ID], 
  [Event Management Team Contact Info].[Associate Name], BIA.Plan, BIA.[Process ID], 
  BIA.Process, BIA.City, Mid([Building],InStr(1,[Building],"#")+1,50) AS Address, BIA.RTO, 
  BIA.Rating, BIA.FTE, [Event Management Team Contact Info].Team, 
  [Event Management Team Contact Info].Site
FROM [Event Management Team Contact Info] LEFT JOIN BIA ON 
  ([Event Management Team Contact Info].Division = BIA.Division) AND 
  ([Event Management Team Contact Info].City = BIA.City)
WHERE (((BIA.City) Is Not Null) AND 
  (([Event Management Team Contact Info].Team)="Event Mgmt"));