When closing SteamVR while in playmode unity will often crash. This may also happen sometimes when not in playmode, I'm not entirely sure. Though it happens often to me.
Here's the error from the stack trace:
{noformat} at <0xffffffff> at System.Object:wrapper_native_00007FF83619F2A0 <0x00617> at Valve.VR.CVRSystem:PollNextEvent <0x001e0> at Valve.VR.SteamVR_Render:Update <0x0013a> at System.Object:runtime_invoke_void__this__ <0x00087>{noformat}
Using the Valve Index, Unity Version 2022.3.4f1, UltimateXR framework