Unexpected dataloader request/load behavior with multiple Sources

Describe the bug

A dataloader load for one source triggers db queries for pending requests for other sources as well.

Versions

graphql version: 1.12.16
rails (or other framework): rails 6.1.3.1

Steps to reproduce

If dataloader has pending requests for Source A,

dataloader.with(Sources::A).request(1)

and then receives a call to load for Source B,

dataloader.with(Sources::B).load(2)

it queries the db for both the Source B data and the Source A data.

Expected behavior

I expected this scenario to only query the db for Source B data, allowing me to queue up further requests for Source A before finally running its db query.

I'm not sure whether this is a bug or a misunderstanding on my part (and I apologize if that's the case).

Actual behavior

The load for Source B executing pending data requests for both sources, meaning if I wasn't done collecting all my Source A data requests, I end up making two trips to the Source A db table.

Start by reproducing the two-Source scenario with graphql 1.12.16 and Rails 6.1.3.1: queue a request for Sources::A, then load Sources::B, and observe which database queries run. Trace the dataloader request/load path and verify that loading Source B does not execute pending Source A requests until Source A is explicitly loaded.