The problem is that you setup your system wrong and not as described in the multiserver documentation. Its a system requirement of ispconfig that each server in a cluster has its own local mysql database. ISPConfig uses this local database for caching and redundancy. So using the ame database for a mster and slave makes no sense and is not supported by ispconfig. So what you report here is not a bug, its just that you setup our systems in a way that is not supported by ispconfig.
Please see multiserver documentation on how to setup a multiserver system correctly so that it fullfills the system requirements: