Old Matrix HQ is not visible in the Rooms list

I'm still in Old Matrix HQ (!cURbafjkfsMDVwdRDQ:matrix.org) as well as new Matrix HQ (!QtykxKocfZaZOUrTwp:matrix.org). However, the former doesn't show up in Riot iOS any more.

Start by reproducing the issue in Riot iOS with both supplied Matrix room IDs and checking the Rooms list. Trace why Old Matrix HQ is omitted while new Matrix HQ is visible. Done means the former room appears in the Rooms list; the issue provides no version, logs, files, or tests to narrow the investigation.

Written by the indexing model from the issue text.