It happens all the time. It’s incredibly rare, even for the absolute best teams to just dominate everyone for an entire season. There were a few games during the early 2000’s where they were clearly sleepwalking and the games ended up being closer than most would expect. The BC game obviously but they also edged out a very average Virginia Tech team in Blacksburg to end the season. On paper that game should have been a blowout. In 2002, they had a one point win against a 5 loss FSU team. And a seven point win against Pitt. Fans got ****ed when we only beat Pitt by 12 in 2020 and the talent levels aren’t even close to 2002’s team. Even wins against garbage teams Temple (44-21) and Rutgers (42-17) to weren't flawless exhibitions.
It's why I laugh when fans today expect blowouts against every ACC team not named Clemson. If the 2001-2002 teams occasionally struggled putting away mediocre teams what makes people think today’s teams should be able to do it so easily? Even on the most stacked team in history, you still had to bring your A game to get wins against decent teams.