A ReloadUI does clear stuff from before, you do not carry anything over.
All that could be carried over is saved in your addons SavedVariables as they are written to disk at the reloadui and read afterwards again.
So if you experience bugs you should check them (SVs) first
But the user interface and events etc. do not save old states unless there is something saved on server side outside of the addons.
If you reload the UI your addon will be loaded totally new -> EVENT_ADD_ON_LOADED -> other events and code etc.