Not sure if it was the same bug, but I had a storage issue where System Data ballooned to like 200GB.
It had the most bizarre solution; airplane mode, set time to one year in the future, reboot, wait a few minutes, set time to 6mo in the future, reboot, wait a few minutes, set time to now, reboot. Went from 200GB to like 15GB. Was ridiculous.
(For anyone looking at this and considering doing it, you also need to ensure iMessage retention is forever, otherwise the iPhone will think it's a year old and delete the messages)
It had the most bizarre solution; airplane mode, set time to one year in the future, reboot, wait a few minutes, set time to 6mo in the future, reboot, wait a few minutes, set time to now, reboot. Went from 200GB to like 15GB. Was ridiculous.
(For anyone looking at this and considering doing it, you also need to ensure iMessage retention is forever, otherwise the iPhone will think it's a year old and delete the messages)