To support your thought -- https://arstechnica.com/information-technology/2016/11/for-f...
Since it's not happening to everyone (check the original twitter thread), I'm 100% sure it's third party apps writing in small 4kb chunks with O_DIRECT file opened, therefore creating write amplification effect where 4kb write becomes SSD block size write (for example 4mb), therefore one 4kb write per second, instead of being 0.3GB/day, becomes 345.6GB/day.