Usercentrics and Google Analytics 4 (or other sessions based tracking tools) might have a significant discrepancy over the same period of time. This is an expected result based on two main factors:
Different definitions of a session
The two platforms use the same technical term, "session", but define and track it differently. This is because both tools serve different purposes and operate with different data.
Different tracking conditions
Usercentrics, as the consent source itself, loads on every page, as it is the tool responsible for collecting and managing consent before any other tracking can take place. Google Analytics 4, on the other hand, depends on the consent granted by the user and the implementation of Google Consent Mode. If GA4 is not given the appropriate consent, it cannot initiate or accurately track a session. This means that over the same period of time, Usercentrics will count every session, while GA4 will only do so when both the technical conditions and consent requirements are satisfied.