HTML5 content behavior after Adobe Captivate deployment

For content deployed with Captivate, I tried to enter characters in the text entry box from the iPad Safari browser, but the characters are not displayed on the screen. (It feels like transparent characters are being input)
The text itself is entered, but it is invisible on the screen.
The same thing did not happen during the live preview, but nobody knows what caused it.
Please let me know if anyone can come up with a solution or cause.

The following is the environment I use.

Version: Trial Version 11.5.1.499
Device used: iPad 6th Generation