From the docs-
(just sent this to a team member so had it handy)
Hi all, I tried the feature a couple of times now and am not sure whether our database is throwing it off or something else because the inferred field is empty. I activated a program today for a send tomorrow and Marketo wanted to send the email within 15 minutes even tho' my list of only 6 people were all in the US with max. 3 hours ahead regarding the time zone. I suspect this happened because some of the contacts don't have the field inferred state filled out. Did anybody experience similar issues?
Thanks,
Yulya