When Would a Vehicle Transition from missing or non_contactable to available via *_drop_off Events?

[viestat]

I found the following state transitions in the micromobility mode specification to be somewhat confusing:

1. From state non_contactable to available with event type agency_drop_off.
2. From state non_contactable to available with event type provider_drop_off.
3. From state missing to available with event type agency_drop_off.
4. From state missing to available with event type provider_drop_off.

What stands out is that neither the non_contactable nor the missing states appear to be entered through a corresponding "pickup" event (i.e., agency_pick_up for agency_drop_off, and compliance_pick_up, maintenance_pick_up, or rebalance_pick_up for provider_drop_off).

This raises the question: under what circumstances would these transitions actually take place?