Reproduction steps:
1. Open the attached project ("case_1244895-AddressableSpriteTests.zip")
2. Open the repro scene ("SampleScene")
3. Select all 'SpriteTestA' objects in the Hierarchy
4. Notice in the Inspector that all SubAssetReferences are set to A
5. While having all of them selected, change the sub-asset to B

Expected result: All selected objects change their sub-assets to B
Actual result: Only one of the selected objects change their sub-asset to B

Reproducible with: 2018.4.23f1, 2019.3.14f1, 2020.1.0b9, 2020.2.0a11

Note: Issue is also reproducible with regular AssetReference drawers