The built-in column names are all fine; but the names of the columns containing user data have been changed to values which often begin with "OData_". (See columns in attached screenshot.)
I'm having the same thing. Automatic Refresh doesn't sync anymore and complains about missing columns in the data source. After investigating I found out that all of the mentioned columns shouldn't be there at all!
I am having a similar issue, I can deal with the added columns but PBI is truncating some of my column descriptions and putting wierd characters in its place.