The BBC aired this story as a documentary in 2015 as part of the Panorama series. They received threats from the Post Office over the content.

> The Post Office threatened and lied to the BBC in a failed effort to suppress key evidence that helped clear postmasters in the Horizon scandal.

> The Post Office's false claims did not stop the programme, but they did cause the BBC to delay the broadcast by several weeks.

https://www.bbc.com/news/uk-67884743

It wasn't just a "glitch" -- it was also a PR campaign (quite successful up to now) that supporessed the voices of those affected.