I get this quit message rarely, but this inconveniences, mainly because the bots are long to return. I almost always have to appeal and to restart the process.
Does some exist possibility to eliminate this problem definitively?
You could set check-mode-r to 0, which will prevent your eggdrop from disconnecting from the server. However, that will leave your bot severely inhibited, as clients with usermode +r cannot change nicks, use channel operator privileges, and such.
The best way to eliminate the problem, is to make sure your eggdrop always matches an I-line rather than i-line when connecting. That is, only connect your eggdrop to servers who wont restrict your eggdrop.