Depending on how many notes you’re playing, the number of tracks running simultaneously, or the overall processing capability of your iPad, the sound may be interrupted due to high CPU usage. If this occurs, go to iOS' Settings > "Gadget" > "Audio Latency”, and try changing the latency setting to "Safer". Or, try using the Freeze function to lower the CPU usage.
Please refer to "Approximate number of devices and tracks" on the product page.
Link to number of devices and tracks is broken.