[martius]

Short answer, yes, a PM should have been consulted and give their approval for the change.

In the scenario I described above (again, it's a guess, I don't know what actually happened), it's possible that the PM was bypassed because the engineers for a reason they thought was good. For example:

* they didn't even think about involving a PM because that's something you have never done,

* the people who wrote/reviewed the change assumed the conversation already happened,

* they were pressured to move fast to mitigate an imminent or existing problem (performance, scalability, ...),

* the PM who should have made this call "left" the company and didn't (get a chance to) hand-off their responsibilities.

I guess what I mean with these comments is that sometimes there are misses like this. Maybe it's a sign of a systematic failure and that internal processes should be improved, but I don't think it means that the company is fundamentally unable to handle these changes correctly or can't make the right technical or product decisions.