I know that 2 way binding worked before winter release. Unfortunately with sandboxes updates this back door was closed. So you cannot pass attribute from aura to lwc component then update it in lwc and handle changes in aura. Does anybody have same problems with data binding in LWC?
Lightning Web Components have always been 1 way as indicated in the documentation:
The data binding between components for property values is one-way.
To communicate down from a parent component to a child component, set a property or call a method on the child component.
To communicate up from a child component to a parent component, send an event.
The update probably corrected a bug which you might had though was something that was working as expected. If you strongly feel that what you have should continue working, i'd encourage you to edit your post with a minimal reproduce-able code sample.