Github reads previously merged files as new file changes

Question

Admittedly I don't understand Git well enough, so I'd really appreciate someone's help here.

Situation:

• We are working off feature branches, branched from test (equivalent to master for this case).
• When we merge PRs we always squash & merge

The Issue:

• PRs detect, in "files changed," files that were JUST merged. In the example below, we merged from dev -> qa, then created a new PR from dev -> qa, and it shows the same files as changed and includes commits that were just merged.

Thanks so much for your help!

First merge:

Second PR: