The stats (number of views) from Delve are different compared to classic SP stats

We've created a Delve board to put our company policies.

The policies were uploaded in a standard Team Site.

When comparing the Delve views with the Popularity Trends of an individual file we notice a significant difference in the number of hits/views? We encounter deviations for all docs on the Delve board.

Is there an explanation for this deviation?

According to the Popularity Trends per file in 4 months time:

- 872 hits by 609 unique users for Group Travel Policy

- 127 hits by 96 unique users for the Social Media Policy

According to the Delve board we have:

- 891 views for GTP

- 134 views for SMP