Using negative conditions and "OR" in a segment does not return the correct results.
When using negative conditions, it is highly recommended to use the "AND" logic.
When it comes to segments using negative conditions (i.e. “tag does not exist” or “not in list”), if the idea is to exclude anyone who has either of those things, you want to connect the conditions with “AND”, not “OR”. It sounds counterintuitive, but using “OR” makes it so if any conditions are true, the contact is considered meeting the conditions to be included. If a contact did not have the tag but was on the list because the “does not have tag” condition is true, the list becomes irrelevant.
Conversely, using “AND” with a negative condition operates more like “NOR”, as all of the conditions must be true in order to meet the rules for inclusion. It can help to think more in terms of sentence grammar, so if you were to use “AND” in this case, it would read more like:
“If a contact does not have [tag] AND they are also not in [list], send them this email”
If either of those conditions isn’t true (either by having the tag or being in the list), the “AND” makes it so that the conditions are “all or nothing”, so only those who have neither the tag "NOR" the list would receive the email.
Using "OR" with a negative condition.
How to use and/or conditions in ActiveCampaign segments