In many senses, internal staff having access to plaintext passwords is a breach.
It’s also impossible to say that I am not responsible for a breach of your private data either. How much should the Irish Data Protection Commission fine me?
If you had my private data written in the back of a notebook, that you carried around with you to coffee shops, for a few days, I'd feel substantially better than if you did it for a few years.
Likelihood that someone peeked scales with time.
Secrets laying in an accessible place for 7 years... reasonable expectation is someone looked at them.
But somebody incidentally seeing them, and maybe, maybe not recognising they were passwords is not a breach. Somebody intentionally misusing them would be, and I haven’t seen anything to suggest there’s a reasonable expectation that that occurred.
A reasonable expectation is also not the standard of proof I’d generally like to see from a government attempting to enforce a penalty.
There is no evidence any unauthorised party gained access to any private data as a result of this incident. There is no evidence that any authorised party misused data as a result of this incident. A “breach” that involves no unauthorised access, and no misuse is not a breach.
A control failure occurred, and it was remedied in the most appropriate way possible.
For instance, Bob imprisoned for car bomb rather than Bob imprisoned after judgement rules deaths unlawfully resulted from Bob's malicious car bombing. Had Bob's car bomb been on a film set and no one hurt, Bob would hopefully be fine.
If you read coverage with this in mind, then what matters is more a case of how likely an action is to be unlawful and thus how lazy the publication is being.
If someone blows up a car, we'd assume it was unlawful. If a company stores passwords unlawfully we'd assume it was unlawful and hopefully for good reason...
From GDPR: "personal data breach’ means a breach of security leading to the accidental or unlawful destruction, loss, alteration, unauthorised disclosure of, or access to, personal data transmitted, stored or otherwise processed"
A typical security policy for securing passwords is to never store them in plaintext.
It would be a rare situation for the storage to not be accessible (what would be the point of storing it).
Thus it would seem fair to assume that in most cases plain text storage of passwords would be a breach of security (internal controls breach) would implicitly also be a breach of personal data (legal definition) as it would at the very least be accidentally accessible to staff, contractors or third parties (whoever hosts the storage).
So, it will likely fit the definition of a breach.
But, it still needs to escalate to a point where it would be recognised as serious enough to warrant action (like reporting to data subjects or regulators).
There are situations where storing passwords in plaintext may not warrant reporting or fines, such as if upon realising the breach it was evident that nobody had accessed the data and it was destructed before harm could be realised; but I doubt anyone would ever know about these situations happening in companies so it's fair to assume they wouldn't reach major news sites.
At at least one point in my career, I have also accidentally mishandled password data (I accidentally leaked them into a log one time - well one time that I know of at least). When I did that I caused a control to fail, and I caused a security incident that required follow up remediation work (including password resets and disclosure), which is exactly what happened here. But I did not cause a data breach to occur. I struggle to image a world where I could have caused my employer to be fined $102M for that incident, and for that to be deemed a data breach, when there is no evidence (presented or referenced in this article at least) that a breach ever occurred. If I leave the office and forget to lock the door, I've caused a control failure. But if nobody comes in to rob us, then I haven't caused a robbery or a breach or anything else like that to occur, even if a typical security policy might require me to lock the door before leaving.
The creativity required to come to this conclusion doesn't do anything to improve the credibility of the GDPR, which from an outside perspective really doesn't look like anything other than an import tariff on foreign tech in disguise.
In the case you mention it seems that happened too: internal actors could reach plaintext passwords and thus for safety the company responded by forcing password reset and disclosure (commendable as I know of companies that would not).
The term "personal data breach" is useful because it defines the range of breaches that the law focuses on (it's not interested in business data or incidents where the first layer of defence fell but the second kept it secure).
I feel it's a bit like having a determination for "road traffic incident". It helps the public, police, etc identify what is in scope... just because you have one doesn't mean you'll lose your licence or be fined - that depends on a range of factors regarding the lead up to the incident: what happened before, during and after. Similar with data breaches.
If a company has a breach it does not mean much in GDPR unless other factors are considered, so I wouldn't worry about being too focused on the term breach.