HW kbd Failed to set (null) as keyboard focus ios
I've just encountered this exception running a Xamarin app on the simulator. It started occurring after I toggled the software keyboard off while debugging the app. Given the exception mentioning the keyboard I think that's what caused it.
Uninstalling the app from the emulator, cleaning and rebuilding fixed the issue for me.
Unsure if this bug is on Apple's side or Xamarin's.
The only references I could find related to Xamarin was close, but the inverse of this - the app crashing on the simulator, but working on an actual device. The resolution in that forum post doesn't describe what the problem might be, but does suggest that cleaning the project and rebuilding may resolve it.
The specific message HW kbd Failed to set (null) as keyboard focus ios is related to the app crashing, but there's no additional information in the pastebin to really help pin down why it's crashing.
You might also consider adding logging statements in your code to see if you can isolate the issue.