SQL Tables importing without associated data types

None, it's the out of the box SQL Server connector from Power Query. The only inputs it's taking is the SQL string and DB, then navigating to the table in question. 

let
   Source = Sql.Database(sqlserver, db)
   Table = Source{[Schema="dbo",Item=tablename]}[Data]
in
   Table

 Agree, it doesn't seem to be a widespread issue, this is the first time I've come across an issue like this. Just tested with a sandbox WorldWideImporters DB and the native query generated brings through datatypes fine. 

Odd!