Every light, both infinite & spot, has a ShadowCam. Even with the light's Cast Shadows property turned off, the Shadowcam remains and just does nothing until Cast Shadows is turned back on.

When you create or delete a light, its corresponding ShadowCam will be created or deleted along with the light.

Sometimes the names can get scrambled so the light and its shadowcam names don't quite match in the menu, but there's still one cam for each light.
The only exception I'm aware of can occur if you delete all the lights before importing a lightset. Sometimes this results in a light without a shadowcam, and which cannot cast shadows.