It only takes one bit wrong to fuck your file system.
And then there’s the same problem with MLC SSDs which are just arrays of capacitors encoding that state as different charge potentials. As a former EE, capacitors leak regardless of implementation.
Also SSDs scare me more. MLC disks have so many states stored in a capacitor that is trusted not to leak over the lifetime of the device. All it takes is a few electrons to go walkies and it’s game over.
The chances of memory failure ruining data are extremely slim; lower than for hardware failure. If you care about your data, back it up.
As for the source of the error, we can only speculate but the possibility of a flipped bit is higher than you think.
Try running memtest86 on a PC without ECC for a week. You will be surprised at the results. I’ve seen perhaps 3 or 4 failures of this in new hardware. DRAM is not perfect.