If you are using Round Robin, that means the samples are being used in a circle by chronological order, meaning it goes through a sequence of the same sample until it goes back to sample 1 think of it as a circle and the engine moves on to the next sample after the previous one has been played, this is different to how superior works in that is has 30 samples that are randomly chosen however the same sample cannot be played again until the rest have been used. Either way that all is a sample for what is called multisampling
Even if you had 3 samples max, that would still prevent a moderate amount of machine gunning. In any sequencer or VSTi there is the possibility of turning off the multisampling which would cause that to happen and some instruments default is set with the multisampling off, so for starters double check to make sure your multisampling is enabled.