Ah right. This was a deliberate design change - previously when you mapped aggregation channels with no category channel, it resulted in a single bar with multiple series. Now it shows each value as a category. If you want the old behaviour you could add a calculated field with am empty string value and put that in the category channel. Sorry for breaking your charts… We think the new behaviour is more sensible most of the time, but I see that the change was unexpected/unwanted in your case.
Regarding the off centre numbers, we’ll need to look into that.
Tom