I have a situation where I was auditing an internal team that was supposed to audit their work monthly. It seems that the manager responsible (no longer with the company) simply stopped doing it about 6 months before leaving. It's obviously an audit finding, but what's the root cause when someone simply stopped doing their job... and they're no longer available to explain why?
Thoughts?
It might be helpful to rephrase this in terms of process:
what is the root cause when this process simply stops being performed?
This gets us out of the realm of psychology and blame, and into the realm of systems and processes.
From a PDCA perspective, it seems clear (as has already been pointed out) that
Check (monitoring/measuring) was probably missing or inadequate, and/or perhaps, whatever process was supposed to be monitoring these audit results did not
Act once they realized they were no longer receiving the audit results. (Again, as has been pointed out, maybe they didn't act because the info was pointless to being with, and so they were fine with its absence, but that's (mostly) psychology and not process.) Looking into the 'whys' for whichever (or both) of those proximal cause(s) would be the next step in my RCA.