The other day I plugged my cell phone charger into my bathroom outlet, it was charging all night and when I woke up that moring my phone was ringing while still plugged in and the wall outlet was making a noise like something was sparking in the outlet. So I got a wall outlet tester that test for open grounds, open neutrals,etc.. Everything tested OK but a couple of outlets in the garage tested Open Neutral.
To get to the question is what would cause the wall outlet to make that noise, and how do I fix the open neutral in the garage and does it have anything to do with bathroom outlet?

I would check the Load side of the Bathroom outlet for power, may have a loose or burned connection. This is a GFI?