Earlier quoted context omitted.
Indeed, the dependence on a persistent connection itself is an absolute non-starter for this feature. It's statistically guaranteed to fail, and IRC as a protocol spec is powerless to do anything other than shrug.
Having been on IRC for maybe two decades now, I find the impermanence to be part of IRC's charm. People engage with you when you ask them what has been going on; just like in real life. It's a social protocol.
The most obvious version of this is a netsplit, but even single users can get isolated from the network and have all of their messages dropped without realizing it until minutes later (if ever). There's no cool name for that; it's just IRC being unreliable.
Maybe unreliability is part of the charm for you, but that bug is absolutely not a feature, and not intrinsic to being a "social protocol."