From 9to5 Mac:
Some advanced users have been reporting an overuse of the SSD for writing and reading data on the newly-released Macs with M1, Apple’s first computer chip based on ARM architecture. The issue could eventually affect the lifespan of the internal SSD used in M1 Macs — not to mention the machine itself.
My betting is on this being a bug in the software being used to measure SSD usage (a utility called smartmontools that can be installed via Homebrew). SSD usage seems like something that should be pretty easy to automate testing for, and so for this to be a bug would be a major omission from Apple’s test suite. Not impossible of course.