I've seen similar symbols appear when migrated from NX4 to NX7.5. It's probably suppressed as John stated, but i also believe it's non geometrical, if you right click on it and go to properties you will see that Component is Non-geometric is checked, uncheck and the component will be visible.
As of what is causing this behavior????
Best regards,
Michaël.
NX7.5.4.4 + TC Unified 8.3
Win 7 64 bit