Building a PR records result against the Commit ID, ignores destination branch

[Rich S.]

1. create PR 1 to merge branch A (at commit id 1111) to branch B

2. run a build; result of build was successful, commit id 1111 marked as build succeeded

3. create PR 2: merge branch A (at same commit id) to master

4. "build" not necessary since commit id 1111 is already marked as build successful ?!?

Is there any way to differentiate between commit id 1111 built successfully against the merge to branch B vs. commit id 1111 merged to master?