Temporary data discrepancies
More direct traffic in Audience > Cross Device > Channels report than in Acquisition > All Traffic > Channels report.
When you activate Google signals, there is initially no campaign history associated with the Google users who have turned on Ads Personalization. When those users are returning users, their traffic is initially categorized as direct. Starting with that first visit after activating Google signals, Analytics starts collecting campaign histories for those users, and eventually the numbers in the Channels reports align.
New Users count is temporarily inflated in the Cross Device reports
In the Cross Device reports, Google users who have turned on Ads Personalization are recognized as new users the first time they initiate a session on a property after they activate Google signals, even if they have previously initiated sessions on the property.
Ongoing data discrepancies
In the Cross Device reports, there may be slight differences between new users in the Channels and Acquisition Device reports.
The Channels report is based on pre-aggregated data, while the Acquisition Device report is based on data that is aggregated at query time, and sampling affects the data differently in each case.
If only a small percentage of users have turned on Ads Personalization, then Analytics has less data on which to model the cross-device behavior of your users, and you can expect discrepancies.
Data must also meet Analytics standards for how accurately we estimate cross-device behavior for your whole user base. If Analytics isn't confident in the accuracy of the estimation, then it doesn't display data values. In addition, Analytics applies thresholds to ensure privacy. If there isn't a sufficient volume of data to ensure privacy, then Analytics does not display data values. If data is missing from either report for these reasons, then the values can differ between the reports.
In reports other than the Cross Device reports, the new-user count could be higher over the long term. In Cross Device reports, users are deduplicated across devices: for example, if a user's first session is on a phone and the second session is on a tablet, then that user is a new user on the phone and a returning visitor on the tablet. In other reports where users are not deduplicated across devices, that same user would be a new user on the phone and a new user on the tablet.