scambra/devise_invitable — comment on commit f8b283bb9f82a1118db268b5f5ad9bd6e0413b74
File: lib/devise_invitable/model.rb line 134
By scambra:

invitable.valid? is not run in your code when invitable is new record, so blank email, or invalid email (which should not exist yet) will give a new record which won't run validations.

Anyway, I have fixed it, changing a bit your code in a7105842f77cfaf7a9f579a43f7d1a324ada8292