Based on what we reviewed together, the behaviour appears most likely related to one of the installed solutions within Solution Center reapplying or regenerating the monitors automatically.

We identified that a number of the monitors returning were internal/system-generated monitors, particularly around AV and No Contact (NC) monitoring. These types of monitors can sometimes be recreated by associated solutions, plugins, or monitor packs even after deletion.

At this stage, it appears the behaviour may have been triggered by either a recent Solution Center update, plugin refresh, internal monitor regeneration,