What is it? See platformio-vscode-ide/project.js at 59f3893216e849494784a846a30a9f2aa8cbeffc · platformio/platformio-vscode-ide · GitHub
How did you receive pio.exe on macOS?
It seems you got a shared project from a Windows machine with hardcoded tasks.json. Please remove tasks.json from .vscode folder and restart VScode.