Members of cohort 2017 in lists do not reference correctly

One-sentence description

Links to member pages route incorrectly

Current behaviour

When clicking on a member of cohort 2017 (for example in the member list or an event), the loaded page is of a random other member (of cohort 2017?). As far as I have seen, the (wrongly) loaded pages are consistent for each member.

Expected behaviour

When clicking a link to a member page, the page of that member loads.

Steps to reproduce

1. Go to the member list / go to an event with subscriptions from members of cohort 2017
2. Click on a member of cohort 2017
3. The page loaded is of another random member.