When using the Carry On mod, it is possible to duplicate the Mob Spring when picking up any linked mob.

To recreate, link two entities together (such as minecarts), and then pick up one of them. Both of the entities will drop a separate spring.

Minecraft 1.18.2
Forge - 40.1.73
Moreminecarts-1.4.6
Carryon-1.18.2-1.17.0.8