If STO setting is configured as "Send at Einstein's optimal default time".
For example, if STO is set for 4 hours and optimal time for subscribers with not enough data falls outside the 4 hours window.
Like if journey goes live at 9am with STO 4 hours then email activity but optimal time is 5pm, that means STO will still trigger the email within 4 hours window right? possibly end of 4 hours? and it is NOT going to hold the subscribers OUTSIDE the 4 hours window? assuming STO will pick optimal time within those 4 hours.