That an error and appears to have been copied from the Electron, E Series, etc… On earlier devices the VIN maximum recommended voltage was listed as 12V max. However, it’s always actually been 17V (not 18V, I mis-remembered the value), with an absolute maximum of 22V.
In the recommended operating conditions for the Tracker SoM it is listed correctly as 17.0V, the other mentions of 12V should be changed to 17V.