Credit Usage Question (Sonnet)

I have noticed that a fair chunk of my credits for my deployed chatbot is being used up by Cluade 4 Sonnet, however I don't have any blocks enabled in my workflow that use this model. I confirmed this by opening the .vf file of the project in an IDE and searching for any occurences of 'Sonnet'.

Is there some sort of background activity that is using Sonnet? Or is it default for anything that wouldn't show up within the source code of the project file?

Thanks!