CSV uploads are not completed instantaneously; they are queued and completed when resources are available. This is usually completed very quickly but can take up to 24 hours.
The default maximum number of contacts entering an automation flow in one go is 1000.
Ometria checks for contacts that satisfy an automation trigger every few minutes. When these contacts are identified, Ometria enters up to 1000 of them in the flow.
If you are mass uploading your contacts to a segment, be aware that the campaign won’t trigger more than 1000 contacts at a time, and the remaining contacts will be ignored. To avoid this, upload your contacts in batches of 1000.
For welcome campaigns, the timestamp is important and should be now or in the future.