Reproduction steps:
1. Open the attached “repro_IN-94426“ project
2. Open the “Assets/Scenes/TestingScene.unity“ Scene
3. Enter the Play Mode
4. Observe the Console

Expected result: No errors appear in the Console
Actual result: “Unable to use a named GUIStyle without a current skin. Most likely you need to move your GUIStyle initialization code to OnGUI“ error appears in the Console

Reproducible with: 2023.2.0a19, 6000.0.37f1, 6000.1.0b5, 6000.2.0a2
Not reproducible with: 2022.3.57f1, 2023.2.0a18

Reproducible on: Windows 10 (22H2)
Not reproducible on: No other environments tested

Notes:

• Not reproducible after changing the layout style
• Not reproducible after closing both Inspector tabs