Every formatter I know errors out if the file is syntactically invalid.
One example I can remember was an empty if or for loop body where everything beyond it was raised into its scope.
I'm taking about pycharm formatter specifically here. This does also happen with braces sometimes, but this would've simply been a syntax error in most other languages or just pulled up the single next line not the entire following code.
if foo:
bar
That's a syntax error, and a good formatter won't do anything about it. If PyCharm's formatter changes it, I wouldn't use it.