Page statistics for custom post types missing before 1st May

[g4rf]

Hello,

a customer of mine showed me a strange behaviour for the statistics of a single page:

Since a few weeks ago the statistics for a custom post type was okay. Since at latest 8th June the statistics only show click counts since 1st May, also for posts that are much older (the example shown here is a post from 2016):

For normal posts and pages the statistics seems to be working as expected.

The plugin is up to date (automatic updates).

Thanks in advance, Jan