I tried talking to Yuri's friend to advance the quest but instead of a dialogue conversation triggering the clock just disappeared and nothing else happened until I advanced time. This happened twice in a row so I have to assume it's a bug
Excuse me, but I'm testing if it works and it works fine for me. Are you sure you are talking to the right person? She is this girl, in the gym. If it's her, haven't you had the bad luck that she just disappears when you go to talk to her because time passes? She leaves the gym at 16:00 and then she comes back at 20:00. Have you tried talking to her at a good time?
If you have done all of the above, have you done anything in your game apart from strictly completing the main story quests, have you done anything even minimally different? Anything could help me detect the bug.