I know this thread is ancient but upon searching it's all that came up for the issue. We're seeing this in a clean 10.5 build with Ignite enabled. I'm finding a ton of duplicate monitors in numerous places such as the following tabs (as in, created by various Ignite plugins): MSSQL, SharePoint, Exchange. Also seeing some duplicate performance monitors. Can't be good for the load on the LT server, also a pain the butt to clean up. Anybody else experiencing this?