I am on the most current one version and ive already got the dress for rika and i've done both dates with Cecila
Just loaded up a new save to try and see if I can find the problem. I cant seem to find an issue, I was able to trigger the elf scene no problem within 3 days of the walkthrough day. You should have no problem as well as long as you have completed the dates with Cecilia, have started Rika's questline, and are playing on the most recent version of the game downloaded off their Patreon. If you became able to trigger the scene at a later date, let me know why/how so I can amend the walkthrough so people don't have problems in the future.