I've had the same problems for a few years now, but was able to solve it last week, when I realized it was happening everytime it was happening when I would do a "quasar dev" in VSCode. I was able to fix the issue by changing 'open' to false in the devServer section in quasar.conf.js. I'm still able to debug using Safari as long as I go there manually.
devServer: {
https: false,
port: 8080,
open: false, // opens browser window automatically
},