Abnormally high CPU for Shibboleth SP module in IIS

[Nate Klingenstein]

> I don't have the complete details on the version of Windows in use or whether the April updates have been applied

It's Server 2016 and the 2021-03 cumulative update in their instance.  Unless Microsoft backported something in the April fix, that implies the version of Windows is not one of the issues at play here.  I think we'd be hearing more widespread reports if such a change were implicated, anyway.

Either way, we'd both be best served by DEBUG-level shibd logs as Scott pointed out, and I'll get those as soon as feasible.