Bug-Related standard is not shown

I tried to click on a related standard

After that I got the following Error Message

But another user with the same access did not get it and the related standard was also shown if I tried the same standard named “Schutzstufenkonzept” with another policy linked. A refresh of the browser or a reconnect did not solve the issue. The URL shown on the item is also different between the two cases: https://eramba.mil.prehcm.de/policy/document/104?allowForLogged=1 (everything is allright) and https://eramba.mil.prehcm.de/securityPolicies?advanced_filter=1&id=139# (the related standard is not shown).

Any ideas why this could happen?