It is not uncommon for systems to return an “All Normal” status even while things are going down flames all around it. Just because a system reports 100% success for the things that it was taught to track doesn’t mean that the real success rate is anywhere near 100%.
This is because a system can only do what it was taught to do. If you build a system to count the number of lines of data submitted, it will count the number of lines of data that it receives. However, it cannot count the number of lines of data that it never receives. If the process fails due to an external cause, the system cannot report it. The system will believe that it has successfully processed all data but in reality, it has only processed the data which is actually received. Somewhere in a room far removed some poor user is screaming at their computer for not doing what it is supposed to do.
As a rule, I have limited trust for any automatically generated system reports. I’ve seen systems which don’t correctly log user log-ins because it had an incorrect handling of usernames. I’ve seen systems with audit reports that multi-counted everything because it tried to audit itself recursively. I’ve seen processes that were highly manual but the reporting only covered the system side of things.
(Most) Systems can only do what they are told to do. That doesn’t mean that we actually understand what the system is doing. Sometimes the code is incorrect. Sometimes the handling of a situation is executed differently than planned. Sometimes the process has evolved to no longer align with what the system was designed for.