My user can't scroll their mobile browser when they attempt a quiz with Essay Question and Atto HTML Editor.
If I change it to TinyMCE Editor or Plain Text Area, they can scroll
I can confirm that both Andorid and iOS produce the same problem

I've also tried in Moodle 4.2 and 4.1, both version can scroll the Atto HTML Editor
So, my conclusion is only in Moodle 4.3  that have the problem

Moodle Version Moodle 4.3.3+ (Build: 20240215)
Ubuntu Server  20.04.6
nginx 1.18.0
Mariadb 10.6.16
PHP 8.1.27