Public char variables uneditable in Inspector when project setting "Use IMGUI Default Inspector" is enabled

Steps to reproduce:
1. Open the attached “IN-119605” project
2. Select “chars” GameObject in the Hierarchy window
3. Set variable “A” value to “m” inside of “Aaaaa (Script)” Component and press the Enter key
4. Observe the value of “A” variable

Expected result: Variable “A” value was set to “m”
Actual result: Variable “A” value stays blank

Reproducible with: 2023.1.0a20 (be935afddb32), 6000.0.60f1 (f02d6f9f9009), 6000.2.8f1 (e4064264ae96), 6000.3.0b6 (342471dcaf1d), 6000.4.0a2 (417aa67423b3)
Not reproducible with: 2023.1.0a19

Reproduced on: Windows 11
Not reproduced on: No other environment tested

Notes:

• Make sure Project Setting “Use IMGUI Default Inspector” (Edit → Project Settings… → Editor → Inspector) is enabled before reproduction
• Only char type causes this issue