IDOL Search Filter not visible

Hi Guys

A client of ours cannot see the IDOL Search Filter (Facets) within M-Files Client (Version 24.11). Only one employee is affected by this issue, even though they work on a Citrix Server. He is Vault-Admin, so it shouldn't be a permission issue. I already tried clearing local cache and the problem is not just within grouped views, as mentioned in https://support.m-files.com/supportportal/article-details/url?recordId=View-Filter-is-not-Appearing-in-M-Files-Client. Also, the configuration is identical to other productive IDOL-Search Engines, which seem to be fine.

Has anyone ever stumbled upon this issue?

Many thanks for your support in advance and have a great day

Thomas