Steps to reproduce:
1. Open the attached “IN-146452” Project
2. Open Window->TextArea Bug Test
3. Type text into the Window and notice it appears fine
4. In the Project tab, Copy the text from Assets/character-limit-unity-6-5.txt
5. Paste it into the TextArea Bug Test Window multiple times (to get character count greater than or equal to 17406)
6. Observe the text in the Window
Actual result: The text is completely invisible in the Window, but is still present and selectable
Expected result: Text should be visible and selectable in the text area
Reproducible with: 6000.5.0a3, 6000.5.2f1, 6000.6.0b2, 6000.7.0a1
Not Reproducible with: 6000.0.78f1 , 6000.3.19f1, 6000.5.0a2
Reproducible on: macOS 26.5 (M1), Windows 11 (By reporter)
Not reproducible on: No other environments tested
Note: This occurs when the character count is equal or more than 17406