See for instance: OCA/server-ux#1025
Historically, this did not happen because copier did create .rej files which where in turned causing pre-commit to fail due to this:
https://github.com/OCA/server-ux/blob/42089781bde9cb059a2a30217859e1fd8e4121c6/.pre-commit-config.yaml#L29-L35
I don't know why this mechanism does not appear to work anymore.