Sorry for the late reply.

From the Docs

https://api.flutter.dev/flutter/widgets/SliverChildBuilderDelegate/addAutomaticKeepAlives.html

Whether to wrap each child in an AutomaticKeepAlive.

Typically, children in lazy list are wrapped in AutomaticKeepAlive widgets so that children can use KeepAliveNotifications to preserve their state when they would otherwise be garbage collected off-screen.

This feature (and addRepaintBoundaries) must be disabled if the children are going to manually maintain their KeepAlive state. It may also be more efficient to disable this feature if it is known ahead of time that none of the children will ever try to keep themselves alive.