Don't have bonsai specific experience for you on cherry. Those look more like leaf buds to me. I have a chinese quince that continually buds up all winter, that even peeks the leaves. It does not seem to be a problem for C. quince. I cannot say if this will be a problem for your cherry. But it would appear that it may be staying too warm for too long for it to remain dormant. My Japanese maples in shallow pots are always the other tree trying to get a head start, I have to watch my temps carefully when they start to look like pushing. If you are just repotting to a larger or same size container, with little rootwork, then it won't be a problem. If you are changing soil, or need to work the roots hard, then you probably should try to do it before it leafs out.
Maybe set this one in a bit cooler spot for a bit and slow it down...