Where is the best technical explanation of why the Post Office's Horizon system was so buggy? Generally nobody intends to write bad software, do they? So why was it so broken? What actually caused the values to get added up incorrectly?

@[email protected] I just ran across this article which describes two specific bugs. A helpful “what” but nothing on the “how” of the tech process being so broken

theguardian.com/uk-news/2024/j…