It happens all the time and it would be quite a bit of work to prepare a list to the level of un-disputability on my part (which seems to be required as Hacker News is feeling very pro-establishment at the moment), but a recent example of this is the failure of the Iron Dome system against Iranian rockets.
Videos online very, very clearly showed many rockets bypassing the system, with some interceptions in the video that made it all the more obvious how many rockets were not being intercepted. All western media claimed the Iron Dome was exceedingly successful and blocked 90%+ of the missiles. This was also not corroborated by non-western sources. It wasn't until Planet Labs released evidence of dozens of strikes on an airbase that this specific messaging decreased.
At that point, they didn't acknowledge that 'error', but instead shifted the narrative to say that the attack, which Iran gave several hours warning of and had explicitly designed not to take lives, had failed because nobody got killed.
Israel coverage in general is a great topic to witness this phenomenon.
Videos online very, very clearly showed many rockets bypassing the system, with some interceptions in the video that made it all the more obvious how many rockets were not being intercepted. All western media claimed the Iron Dome was exceedingly successful and blocked 90%+ of the missiles. This was also not corroborated by non-western sources. It wasn't until Planet Labs released evidence of dozens of strikes on an airbase that this specific messaging decreased.
At that point, they didn't acknowledge that 'error', but instead shifted the narrative to say that the attack, which Iran gave several hours warning of and had explicitly designed not to take lives, had failed because nobody got killed.
Israel coverage in general is a great topic to witness this phenomenon.