When a domain drops, it's available at every dropcatching place; It's no longer depending on the registrar when it's dropped (The registry handles it)
But prior to the drop, some registrars auction/send their expiry stream to platforms like NJ/GoDaddy.
For Google, it's not evey clear.
I see they sent 1 name to GD expiry auctions and 3 to Namejet lately