When I use the search function on any browser in iOS, the topic scroller jumps to about halfway through the topic, and wants to keep scrolling until it reaches the top of a topic if you continue typing in the search bar:
In a Topic:
On the homepage (with private mode on, only):
This is worse when using private browsing. It occurs using Safari or Chrome, using both an iPad Mini (1st gen) and iPad Air 2. This does not happen using a PC. It happens both on Discourse Meta and the Infinite Flight Community (two I’ve tested this on).