Hi @BAIBA,
Just to make sure I understand you.
You want to know why not all profiles in Klaviyo have a magentostore property assigned is that correct?
If that's the case, and I understand it correctly, then it might be because all integrations push data to Klaviyo and add data to an existing email address (profile) or create new profiles if non exists.
Assuming a newsletter signup is coming from a popup - which has nothing to do with magento - they won't show a mangentostore property.
Magento pushes information to Klaviyo when a customer i.e. places an order. That's when the info starts flowing in.
I'm assuming you have multiple stores but connected it to 1 klaviyo account?
If so separating the various stores might be a bit difficult and having separate Klaviyo accounts might be a better way to integrate the stores separately.
Not sure if this is what you’re looking for. If not please add some more context or examples of what's happening.
Omar Lovert // Polaris Growth // Klaviyo Master Platinum Partner
We help with e-commerce growth through CRO, Klaviyo and CVO