Happens all the time.
Organisation decides they need a change. They advertise for the job but aren’t clear enough about the requirements. Contractors bid for it without fully understanding the requirements. Organisation chooses cheapest bid and commits. Both sides then have an incentive not to ask enough (or the right) questions.
Contractor starts doing what the job description requires, but then start to realise the job is actually far more complex. Often they try to explain this to the organisation, but the department overseeing the implementation of the new system either doesn’t have the budget to pay for the additional work, or starts to try to conceal the problem from the rest of the organisation, hoping that it’ll all just work out (or both).
When the new system goes live, it’s a disaster. But quite often the old system can’t be switched back on because the licence on it has expired.
Ask me how I know…