This can sound very ridiculous, but for my dyslexic brain a small change in the next to paragraph will be a important help.
https://docs.unrealengine.com/en-US/Engine/AI/BehaviorTrees/NodeReference/Composites/index.html
Actual
Selector
If a Selector’s child succeeds, the Selector succeeds. If all the Selector’s children fail, the Selector fails.
Sequence
If a child fails, then the Sequence fails. If all the Sequence’s children succeed, then the Sequence succeeds.
Proposal:
Selector
If a Selector’s child succeeds, the Selector succeeds. If all the Selector’s children fail, the Selector fails and go up.
Sequence
If all the Sequence’s children succeed, then the Sequence succeeds. If a child fails, then the Sequence fails and go up.