When Input Field has Best Fit option turned on writing large text into it sometimes makes cursor appear outside the input field area, and in some cases the whole text gets hidden too. Clicking on the input field once again makes cursor appear near the text as desired.

To reproduce:
1. Open the attached project
2. Open scene1
3. Play the scene
4. Write some lines of text into the Input Field

Desired outcome: Cursor always appears near the end of the text, inside the input field. And at least some text is visible in the input field.
Actual result: Cursor occasionally moves outside the input field. Sometimes whole text is gone.

Reproduced using Windows 10 Pro on 5.3.4f1, 5.2.0f3, 5.1.2f1.
It seems that version 5.2.0f3 had the desired Input Field behaviour.