There’s a serious bug in Unity 2020.1.17f1. It opens Sublime Text 3 multiple instances.
Reproduced the bug while using Mac version of Unity3d 2020.1.17f1 and 2020.1.15f1. Everytime I click on a warning or respectively an error Unity opens a new instance of Sublime Text 3. Happens on Mac OS X 11.0.1 with 32GB RAM. Set Sublime Text 3 as default editor in preferences with arguments.