Unlocked champion bar/shop won't refresh!

Every round the champion bar/store is supposed to refresh if not locked. But it doesn't always. Seems to be happening more frequently- at least 1/4 of the times it should be "refreshing" (during minion waves, between player-to-player combat etc..) it does nothing. I'll see the bar stay the same- blank spaces and all if I had bought a champ the previous round. Makes me waste extra gold on a bug issue. Really annoying.