With #24179 the default_path configuration key was added. Part of this was to allow bundle overrides in /templates/<BundleName>. However, this doesn't appear to be working for Form templates.

Specifically templates in templates/bundles/BundleName/Form/something.html.twig does not override the original. In my case this is for https://github.com/excelwebzone/EWZRecaptchaBundle but I'm guessing this would apply to any Form templates.