Base pose is not shown when enabling Additive on a Pose asset

This is a regression from 4.14.3

1. Open QAGame in the editor
2. Open the Test_Pose asset
3. Enable Additve in the Asset Details panel
4. Select Base from the Base Pose dropdown and click Convert to Additive Pose

Result: Arms are still down at his sides

Expected: Arms are out in the T position