Before_Update Hook Context Doesn't Have CurrentItem?

I’m finding that the before_update hook context isn’t showing the current item.

For my use case, I periodically run a 3rd party API call and bulkSave it into a collection. Between two API calls, edits are made to certain columns nonspecific to the API. Once the subsequent call is made, these edited columns get overwritten as null - which is to be expected with bulkSave.

I was hoping to use a hook to catch the update, insert these edited fields, then pass along the “merged” data.

Referencing:
https://www.wix.com/velo/reference/wix-data/hooks/beforeupdate

Any ideas as to why the documentation shows a “currentItem” context object but I’m not seeing that object?

Thank you!