Error notification displayed at the bottom of the page, when enabling showing annotations on Solr Search page

Steps to reproduce :
1. Login in the wiki (I logged in with the Admin account)
1. Go to Solr Search page
1. From the content menu, select Annotations
1. Click on the checkbox for "Show annotations" to enable it

You will notice an error at the bottom of the page saying : Failed: Wrongly formatted server response . I followed the same steps on other spaces / pages, but I reproduced the issue only on the search page.