GlockApps doesn’t open tested messages and doesn’t mark them as spam/not spam. With the Gmail’s interactive email addresses, it marks tested messages as seen. With the Gmail’s non-interactive email addresses, GlockApps shows no engagement.
As prior user engagement is taken into account by Gmail, you may see the Spam email placement with the Gmail’s non-interactive addresses in consecutive email tests. The email placement can change to ‘Spam’ with interactive Gmail addresses when the reputation of your sending domain is bad, low or medium as the reputation of the domain is more important than prior user engagement.
If you don’t have a consistent email flow coming from your domain every day, for example, system notifications, transaction emails, autoresponders, follow-ups, etc., it is not recommended to run multiple tests for the same message within a short time as Gmail can track this activity and mark your message as spam. Run the tests with an interval of 15-20 minutes to receive as equitable results as possible.