This has happened to me too on my no cheats survival in 12 and 13 and it doesn't seem to be just visitor mode some custom player settings like just recently my friend was killed while he was in Can't build Can't mine Can't use containers and Can't use doors and switches and he didn't drop his inventory and he only dropped what he was wearing. I hope this is fixed.
Joshua Jiang
This has happened to me too on my no cheats survival in 12 and 13 and it doesn't seem to be just visitor mode some custom player settings like just recently my friend was killed while he was in Can't build Can't mine Can't use containers and Can't use doors and switches and he didn't drop his inventory and he only dropped what he was wearing. I hope this is fixed.