Hi Mackenzie,
I guess the fundamental Preventive Action should have been initiated/documented in the original "Monitoring" activity. Whatever that was.
As far as the "Verification Stage" itself, the Preventive Action is presumably related to "Root Cause", eg excessive documentation/workload/procedure. As always. 
IMEX an actual signature is a mandatory, although often eventually automatory, part of the "Verification". Perhaps slightly helps to maintain concentration. And the Overtime Bill.
The acceptable time delay was debated in a previous thread. Opinions varied between 1 day and 1 week, sometimes regardless of official tolerances. Back to Risk Assessment again.