I'm not the Bernard type, but I think this kind of thing is pretty common, unfortunately. In fact it happened to me.
I was pulled over about 12 years ago not because I was driving erratically or anything, but because the lightbulb above my license plate was out. I'd had a few beers over a 4-5 hour period but didn't feel I was intoxicated. And I'd stopped drinking at least an hour before leaving the bar. I was actually giving a couple drunk friends a ride home. I will say that I was much younger then and wouldn't even take that chance today. And this was years before Uber, of course.
Anyway, I did the field sobriety test and performed flawlessly. I did ask the officer to repeat instructions a couple of times because he was very vague/confusing (on purpose, I believe).
It took several months for DPS to hand over the arrest video even though my attorney requested it immediately. Meanwhile I'm without a driver's license because I'd refused the breathalyzer (which I was always told to do if I'd had even one drink.) When my attorney finally gets the video he tells me with a big smile that I look and sound as solid/sober as anyone he's ever seen on tape. But you wouldn't know that from the officer's report. He wrote that I was swaying, slurring, and confused (because I'd asked him to repeat his instructions).
When my attorney showed the video to the prosecutor, he immediately agreed to drop charges if I'd do a few hours of "alcohol counseling" and AA classes. We agreed, with the caveat that my record be expunged, which it was. It still cost me $4000 in attorney costs and various court fees. But I"m sure that's about as cheap as it ever gets.
The other infuriating part of the story is that while my attorney was trying to get hold of the video and locate the trooper who arrested me, he finds out that after my arrest, he had been fired from DPS for altering/deleting video after wrecking his cruiser, and prior to that had been fired from APD for pulling over young ladies without cause and hitting on them. Of course DPS refused to tell my attorney where he was. He was nowhere to be found and didn't show up for my license hearing, which helped me get my DL back.
TLDR: I was pulled over and arrested for DWI and the state trooper lied about how I did on the field sobriety test. Video showed the truth. Trooper turned out to be a dirty cop. Charges were dropped, record expunged.