Here is my two cents. If it bothers you and obviously it does or you would not have posted, then buy your little one a different mini book and sit down and read it with her. Make it special. You know this is exactly what grandma did when she gave it to her. Now you have to undo that, but it is an easy chore because the little person loves you, you have constant contact with her and you are the world to her. She will forget all about the other book and you can lose it.
As for mom, well she knew what she was doing and she got your goat. She is your mom and knows how to get you to react. Now you need to unload. Why? Because if you let the little things slide ? you know there will be a lot more of these ?little things? ? they will build up into a BIG THING and you will pop! (I have been there) So here is my suggestion to get it off your chest. Don?t say anything to mom, I mean absolutely nothing. What mom wants is for you to bring it up so she can save you! So you can finally AWAKE! She put the magazine there for a reason. To get to YOU. She is probably so proud of herself and thinks she did such a great thing. She is waiting for you to call and discuss it all. Your choice to not discuss it will bother her, as much as finding the magazine bothered you. Of course you continue to talk to mom because she is your mom and you are her daughter and you love each other. If she questions you about it, take a deep breath and change the topic. if she insists then tell her thanks but no thanks and end of that discussion and change the topic. If she persists tell her ya gotta run your daughter spilled her juice and talk with her later about mom daughter things.