The Gremlin states:

You must take the Gremlin as a Follower . Whenever you try to use an Object you must first roll 1 die:

1. Discard the Object and lose 1 life
2. Discard the Object and lose 1 life
3. The Object fails to work during this turn
4. The Object fails to work during this turn
5. The Object works and you may discard the Gremlin
6. The Object works and you may discard the Gremlin

Question: Does this mean that the Gremlin does not affect Magic Objects?

Yes. I don't know where to find the rule reference right away but probably under the object section in the base game rule book.

Magic Object is just a subsection of Object. So, all Magic Objects are Objects, but Objects are not necessarily Magic Objects.

You can just click the link to the word "Object", which you pasted in your post, and the answer will appear immediately. Just try.

That's what Wikipedia can do.

Thanks all. I have learned never to trust Wikipedia

Yeah, it's not always clear if a card refers to "Objects" as in "Objects, including Magic Objects" or "Objects, not including Magic Objects". I generally just go with the former interpretation, unless the card explicitly states that it does not include Magic Objects in its effects, like the spell "Transmute".

Also, I personally generally regard wikis as reliable, if only because of the "wisdom of the crowd" effect, i.e. the aggregate opinion/estimate of a group of people is generally more accurate than that of a single person.

I remember this coming up way back in 2nd edition (are magic objects considered objects?), finally we understood it had to be so otherwise there would be several cards and effects that wouldn't make sense.

I was only pointing out that the link on the word "Object" leads to another wiki page where the following words are written:

Both Objects and Magic Objects are classed as Objects. During the game, characters usually acquire Objects as the result of
encounters.

This can be found on the Talisman rulebook, page 12, so it's an official rule of Revised 4th edition.