Link broken in WebUI while it's working on client.

After replacing wiki markup by html tags (Data#2280), there is one link in the description of FOSDEM 2021 Schedule not rendered properly in the WebUI of f-droid.org while it's fine on the client.

WebUI (buggy)

Client (works as expected)


It's not clear to me, why this doesn't work, while another link a few lines above does.
https://gitlab.com/fdroid/fdroiddata/-/blob/master/metadata/info.metadude.android.fosdem.schedule.yml#L57

!(/uploads/157fbe9936536a7fa417c71b5eaef91d/fosdem_working_link.png)
!(/uploads/51acc69727c7b727a4fcc0bf6cced3f2/fosdem_working_link.png)