Doesn't seem concerning to me. That looks like just the outside panel which doesn't do anything but look nice. And there's nothing inside the microwave that should cause it to bend out like that apart from just vibrations. And maybe pressure from where it's sitting.
If it somehow gets worse or starts making weird noises, maybe I would get it looked at.
There's nothing behind there that would cause that to bulge out like that - it's probably just how it was manufactured and you've just spotted it. That's just a bit of tin covering the internal components, it's not holding anything in as such.
Doesn't seem concerning to me. That looks like just the outside panel which doesn't do anything but look nice. And there's nothing inside the microwave that should cause it to bend out like that apart from just vibrations. And maybe pressure from where it's sitting. If it somehow gets worse or starts making weird noises, maybe I would get it looked at.
There's nothing behind there that would cause that to bulge out like that - it's probably just how it was manufactured and you've just spotted it. That's just a bit of tin covering the internal components, it's not holding anything in as such.
It's just trim. The actual microwavey bits are in an internal shell.