Huh, what kind of dodgy IRC servers have you been on ;) ? I've never encountered that in years of IRCing from hosts running Dropbear, though I could see it happening.
Heh I should be more precise. During the summer storm season (for example the attacks last week across most of the popular networks), most networks deploy spambot countermeasures that they don't typically run on a normal day. But when they flip the switch, it tests new connections only. So for example I use ZNC and essentially never disconnect. But I disconnected to renew my LetsEncrypt certs during this time and then was k-lined on reconnection on a couple of networks.
