Good afternoon Suzy and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the tickets being sent too soon to your customers. Yikes!
I would love to help you with this topic.
You are right, the first step to resolution is to disable that checkbox (which was unintentionally problematic in the last couple of releases).
The second step would be to upgrade to our latest versions (4.4.2) since we completely removed that feature and replaced it with a far more comprehensive one (When should tickets be emailed to customers?).
Let me know how that goes.
Best regards,
Geoff B.