Just last week, the OnePlus 7 Pro received a software update that squashes a few bugs, fixes a couple of things and bumps up the security patch to August 2019. Well, today the vanilla 7 is receiving the incremental update as well.
The changelog is quite similar to the one of the 7 Pro although, the Oxygen version is 9.5.8. It optimizes the adaptive brightness, clears the issue with accidental touches during phone calls and takes care of some minor bugs.
As always, it's a staged rollout so the OTA will take some time to reach all users.
That's very unlucky. Never happened with my 5 or 7.
Your's sounds like a faulty device. Because switching off when charging is a very major issue and would be all over the internet. Mine doesn't do that and hope your replaced one doesn't do that as well.
I would love to love OnePlus, and OxygenOS is great - mostly. But, it always has some totally retarded bug that makes the phone unusable. Returned my 7 because it would randomly totally turn off after unplugging from charger. Would then take sever...