Accuracy is obviously an important factor and is something I take seriously. That being said, it isn’t quite perfect despite being well over 99% accurate at the last count. The majority of icons have no trouble at all - most of the issues are with a few very similar icons. I monitor accuracy very closely and may manually correct data if I notice a particular issue. In addition, I regularly review all the icons for a random subset of screenshots.
The TLDR is it’s pretty accurate and the accuracy is monitored closely and should only improve as time goes on.
Note: Object/Kindred/Deja Vu have a tendency to be misidentified, this is a known issue that I am actively working to improve.