FWIW, Stars reporting that Seguin suffered a broken foot in Game 1; confirms Hintz suffered an oblique injury late in Game 6.
https://twitter.com/user/status/1526657672078151682
No info about what "reaction to treatment" caused Hintz to be a late scratch for Game 7. Did they try to give him an injection and hit a nerve or something? Maybe they gave him some Brain and Nerve Tonic and his head swelled up like Ken Griffey Jr on the Simpsons?