What is “the upgrade” (lots of moving parts here, so want to make sure I am clear on that).
I have absolutely no experience with Kubernetes, but on the off chance that this might lead in a helpful direction, the following might be of interest.
For months I have had a link pinned to my Quick Access list in Windows Explorer that took me to the following link, where my persisted WordPress files live.
I haven’t touched this at any point but yesterday discovered it is now broken link.
Rather strangely, I can manually drill down to that exact folder in Explorer, but the folder is empty, even though local WordPress sites remain operational. Confused the heck out of me!
It took me quite some time to discover this, but all my files are now under:
I have no idea when, whether or why this changed but might be worth checking of there is any overlap with your scenario.