There was a fix that landed last night by Atomicdryad that stores the actual monsters you’re ignoring, so that losing sight of a monster briefly doesn’t trigger safe mode when it comes back in sight.
Now if you ignore a monster, it marks it ignored along with the distance to it, and it doesn’t bug you about it unless the distance to it is halved, or it’s 6 moves or closer to you. (I’m not sure about that hard minimum, but we’ll see if there are any legitimate use cases where people want to ignore monsters that close, there may well not be.)