For non-navmesh movement you can use BTTask_MoveDirectlyToward.
Regarding the core of the issue you need to manually abort the Movement AI task (the one that’s created as a result of Move to Location or Actor call, and that you get as its result, the Async Task Proxy). Add Event Receive Abort or Event Receive Abort AI or and call End Task on that Async Task Proxy. You might need to store the Async Task Proxy instance as BT node’s member variable.
Cheers,
–mieszko