You may see the error "The authenticity of host <vcs-info> can't be established." after all git objects have successfully downloaded, or "warning: Clone succeeded, but checkout failed". These would be visible within the checkout step log.
If you encounter either of these errors while using git-lfs it could be due to a bug and has been fixed in recent versions. If you are using git-lfs and encounter these errors add a step to manually update git-lfs before performing the checkout step. Steps for installing on various executors is available here.