Motion Controller component attachments lag behind parent.
Not happening on Oculus Rift
Workaround: Set "Disable Low Latency Update" on your Motion Controller Components to 'true'
User Submitted videos showing problem:
Result: In 4.22+ Attachment lags behind parent
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-74977 in the post.