In order to get the linter to run when changes are made, setting python.linting.lintOnTextChange also requires the user to turn on the setting files.autoSave. This defeats the purpose of this setting. Hence we have decided to deprecate this.

If you require linting of Python files on text change then enable the following settings:

"python.linting.lintOnSave": true,
"files.autoSave": true

If the above solution is not acceptable and you prefer the linter to run without having to save your changes, then please add your vote 👍 against the following issue #408.