Updated subscription - tracking broke down

Hi,

we are facing a strange issue. We just updated our Shopify subscription from Standard to Shopify Advanced. The next day we noticed our sessions went down by -50%. However our conversion is up, and orders come in as before.. We did not make any other changes that could have affected this. We have seen 50% less traffic from almost every source in the last 5 days after updating the subscription. I already regret updating the subscription. Does anyone have similar experiences? Any idea what could be wrong?