I have a metal bumper on mine also, the charger I bought off of Amazon doesn’t stick very well. That back is just too slick, I should be getting a a matte skin from Slickwraps in on Monday. I’m pretty sure that should help a bit. I had put the clear sticker that you would put under a metal plate and it actually stuck to the magnet better. However I didn’t like the look and only used it to experiment.Playing around and decided to put on a bumper. The naked back does not work all that well with the MagSafe puck. It holds but will likely pop off when going over a big bump as I was gently jiggling it and with a little extra force it pops off the MagSafe. View attachment 1674228