See UDN: https://udn.unrealengine.com/s/question/0D54z00009g9wE1CAI/viewextension-is-not-added-when-no-bindings-are-setup-in-the-bindings-view?fromCase=1
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-196972 in the post.