I don’t know whether that’s invoking TrustedInstaller, but I doubt it (else we’d all be seeing issues with it).
There are definitely some things in Relevance you could do that impact system performance / invoke TrustedInstaller. I’d point at this thread for an example of how a WMI query can cause MSInstaller to execute repeatedly due to a WMI query for the Win32_Product class Windows event viewer id 1035
I’d suggest using Sysinternals’ Procmon (www.microsoft.com/sysinternals) to see whether you can identify the fixlet/analysis (.fxf file) that BESClient is referencing just prior to the TrustedInstaller activity. You may find that a custom fixlet/task/Analysis is triggering some TrustedInstaller activity. The most likely way for that to happen would be a WMI query, as there aren’t many other ways for the BESClient to trigger another process on the system outside of running an Action.