Best Practices for SPA calling multiple APIs?

My team is trying to figure out the best architecture for the problem below. I'd like to be able to find any existing recommendations for our situation, but it's difficult to search.

• We have an application A with a SPA, ASP.NET WebAPI backend, and a database.

• We have another in-house WebAPI B for storing and serving files and application-agnostic metadata. This belongs to our team too, but is meant to eventually be consumed by other applications.

A has a table of A-specific document metadata. These records represent attachments of files to other things in A and contain the IDs of the document records in B

To list attachments for a given item, A frontend gets A document records, then uses the result of the call to A to fetch the rest of the metadata (filename, size, etc) from B

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We had an idea to eliminate the second call by duplicating the data returned from an upload to B in A's metadata.

So, my questions are:

1. Is there any reason not to duplicate the data?
2. I've had trouble googling it so far—I feel like I'm missing jargon or some term that will get me what I need. Is there a name for this specific architecture topic that will aid me in my searches?

Thanks