API Not Returning All Item Fields/Data

Hi All!
I have written a few methods to query items/collections via the API. In the past few days I have added a few fields to a collection. However when I query via the API for items in the collection, I am not seeing these new fields. Actually there are many fields I am not seeing via the API, and these fields have been in this collection for quite a while. I first thought maybe it was not returning fields that didn’t have data associated with them, but the fields do have data and still not seeing them via the API. I can clearly see all these fields when I log in directly to the frontend CMS.

Has anybody experienced this before and has any helpful info?

Thanks in advance for your help!

Can you share the code and its output so we can take a better look at it?