It is rated at 1 year after hitting MWI-1.
How far was the M4 past the MWI-1?
It hit MWI-1 at 178TiB. It was up to around 600TiB of writes if memory serves.
Way past MWI 1. If it had been stopped at that point it should have held its data as speced.
After that holding data is questionable to length of time.
Same as asking how long it will continue to write data.
You are all making the new specs with the testing.