Hello @mwallace,
Thank you for posting this question. As @AnnaW kindly pointed out, there are no stupid questions! This is a place for learning and knowledge sharing so I am glad you inquired about this.
Also, thank you so much @ejburney for your helpful tip!
@mwallace, to speak to your question directly, if you have a flow triggered off of a list (and the flow emails are live) and you upload contacts to that list, those newly uploaded users will begin to move through that flow.
There are a couple of ways to prevent this from occurring. The first is to temporarily turn all emails in your welcome flow from live to draft mode pre-upload. Wait about 30 minutes post-upload, and then turn those welcome emails back to live mode.
If you have already imported them into a list triggered off of a live flow, no worries! You can skip them from remaining flow emails by creating a net-new list (not triggering any flow) and re-importing them into that new list. As a side note, since these profiles already exist in Klaviyo, you only need to import their email addresses into the net-new list, we will retain all other data about the profile and no duplicate profiles will be created upon re-upload.
Next, add a flow filter to your flow triggered off of the original (Newsletter) list which reads: “is not in list > (name of new list)”. That will ensure these users who inadvertently entered the welcome flow and may have received an email already do not receive any(more) welcome emails :)
Lastly, in the chance that these users did inadvertently receive a welcome email, say the first one, before being skipped by the filter for the remaining emails, optionally you can send a campaign to the net-new list to say the welcome email send was a mistake.
Hope that is helpful and glad you asked this question because it is more common than you would think!