A white skin or film formed on the surface of my real maple syrup

If it is not mold it is is likely a nontoxic fungus. Don’t worry the syrup is salvageable. Scrape and dispose of the scum on top. Boil the remaining syrup and remove the foam from the top and voila edible syrup.
It should be noted here that mishandling lead to the growth to begin with. Store the syrup in a sanitized (lid and) glass container. (You can sanitize it by boiling in water for 10 mins). Store in refrigerator once opened.

A quick search shows that it’s likely a more-common-than-thought fungus, not harmful, can be removed.
And yes it’s better to store maple syrup in the fridge.
Too much info to repeat here.
Check out 2 or 3 sites to be sure you’re getting latest consensus.