If a BT ends with a latent abort with another BT asset pending initialization, the BehaviorTree component will stop the tree that was aborted, but it does not start the new tree. You can check with an IDE debugger to see that there is a BT asset pending in TreeStartInfo.
The BT component does work as expected to transition to a new BT asset when the original BT ends without a latent abort.
UDN user supplied project with repro setup for testing.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-194946 in the post.