Reproduction steps:
1. Open the attached “Repro.zip” project
2. Open the “Assets/Scenes/SampleScene.unity” Scene
3. Enter the Play Mode
4. Observe the characters in the Scene View
5. Select the “Armature Variant(Clone)”, which is not red in the Scene View
6. Select it’s Left_LowerLeg GameObject in the Hierarchy window (Armature Variant(Clone) > Skeleton > Hips > Left_UpperLeg > Left_LowerLeg)
7. Observe the Transform Component’s Position values in the Inspector window
8. Select the “Armature Variant(Clone)”, which is highlighted in red in the Scene View
9. Repeat 6th and 7th steps
Expected result: Transform Component’s Position values are valid and the Skeleton’s left leg is pointed down
Actual result: Transform Component’s Position values are equal to “NaN” and the Skeleton’s left leg is pointed upwards clipping into the body
Reproducible with: 2020.3.48f1, 2021.3.25f1, 2022.2.18f1, 2023.1.0b16, 2023.2.0a14
Reproducible on: Windows 10 Pro (22H2)
Note: The amount of GameObjects affected is erratic, thus the same