Following the other comments, having the same issue too. Always seems to occur during Ops activites and pinnacle. Always in a fireteam too. No notification to rejoin previous session either. Destiny 2 is also making the console run hot too. Tried with other games for extended gameplay on highest video settings with no issues.
Update: this is now happening when playing solo. Some response from Bungie to any of the comments within this thread, other than "clear cache", as it evidently does not work and is a game issue, would be nice.
We're in the summer, the xbox can accumulate a lot of heat internally, if the air has no way to go up.
I discovered this while playing destiny 2 before EoF, my game overloaded, and crashed to menu, I then increased general ventilation, and air movement at home, then changed the xbox to the vertical position.
When upright, the air coming out the vents, doesn't get anywhere near as hot.