just to be clear there are two discoveries.
snmpcollector Theory of Operations - CA Unified Infrastructure Management Probes - CA Technologies Documentation
Primary discovery is of devices and via discovery wizard.
Secondary is discovery of device components.
I think, in snmpcollector GUI in the main probe section there is "hours between rediscovery" - you can set this value and it will automatically do the component rediscovery every X hours. You could set this to 1, then wait 1 hour, then set it back to 0 to force it. That might work for you.