In certain implementations of software monitoring solutions, the type, quantity, and frequency of monitoring – the system or service checks – can result in an increase in load on the systems being tested. This increased load can lead to the flawed interpretation that additional monitoring tools are necessary to identify the load factors, resulting in further-increased load.

Or, to summarize: throw so much monitoring at a platform that it unexpectedly increases load, which prompts additional monitoring. Repeat.
Or, to summarize the summary: You cannot observe any system without impacting it.