Not that I will be playing in online mode, but Blizzard may have to implement local servers for those who are asking for it.
If I switch between two spells quickly and then cast them, the previous spell will cast first followed by an automatic shot of the newly selected one.
IE: I had fire bolt on the bar, quickly changed to (any other spell) and then cast it quickly. Sorceress will first cast fire bolt and THEN cast the newly assigned spell.
I’d say this is caused by the inherent latency of playing from Oceania on the current beta setup. At least, I hope so…