Not really sure a bug is even possible in a system that wasn't designed. Any 'bugs' would have resulted in iterations that failed. Death has been there in every iteration including the ones that were successful. So I don't believe it's a bug.

It could be a feature because there could well be an evolutionary advantage for iterations of a species where the older, frailer generations die more quickly, thus leaving more resources for the younger generations.

It could also be a hardware limitation but everything we've learned so far about how we die gives us hope to being able to overcome the problems, so in that regard it isn't really a hard limit but more of a natural limit that we might be able to work around.

To that end, I'm going to go with 'feature'. But it's an old feature, and one we won't necessarily use in the future.

Thoughts are with you.