Memory needs to be constantly refreshed to keep it's contents. That's why you lose contents when powers off. However writing new values causes a temporary surge in power to change the bits. This leads to a small EMF (Magnetic field) surge as well. When you hit the same row line over and over again this causes the field to build, till the magnetic field spills over in the adjacent row. This causes the bits to flip. That's how row hammer works. It affected DDR3.
That said, it WAS to be mitigated by restricting how fast the same row could be written too. If they found they could still flip bits, I would be betting it would be on faster memory that runs on a higher voltages. (1.35V)