A syrup like Aunt Jemima or Log Cabin is about 90% Corn Syrup. There is generally less than 7% actual maple syrup in any of those and most don't have any. If you read the label carefully, it should say maple flavor syrup. Any actual maple syrup will cost about 3-5x's per ounce that the standard store bough syrup does. You will need to look for 100% Maple Syrup on the label and in the west/southwest this can be found at Whole Foods, Sprouts, Trader Joes and many supermarkets.
The corn syrup in the Aunt Jemima's is probably what caused the "fake" taste and it will be loaded with preservatives. Ray, you are right, absolutely read the labels on aything you put in your brew. And remember that Maple Syrup has some unfermentable sugar in it, so it won't be as carbonated as a corn sugar or cane sugar primer.
Cider and Juice in the Desert...and I occasionally brew beer.