While trigger is held, vacuum turns on and off repeatedly

I have a Dyson V8 Parquet. When using it with any attachment, sometimes it will rapidly (about once per second) stop and start. The LEDs remain on throughout. Is it possible that the button is not making good contact? It sometimes feels like shifting my finger slightly resolves the problem. The "trigger guard" (thin plastic piece underneath the button) got snapped off at some point, which is part of why I suspect the button may be at fault.