Number of visits from report not match visits in profile

Based on a monthly report, we have a large number of visitors who have visited our portal more than 51 times this month. I wanted to check this now by looking at the visitor profile of the heavy users (> 51 visits). I noticed that in the visitor profile the number of visits of the same month does not match the number of visits in the report. I cannot explain the reason

Can someone help me with this?

Thanks in advance!
Markus