My team enters the cafe at different hours. It seems to confuse the game and I can't give players drinks..

There are multiple timers at play. Bushes restock 22 hours after the previous restock. At the same time, once you give a player a bush, you cannot give them a bush until 22 hours later. If those timers run synchronously, all is good, but if they become staggered, then you may have difficulty giving. To get all the timers running together harmoniously, try holding back from giving bushes for 24 hours.