When jumping with view bobbing on, normally the hand and camera moves a little bit, and falling causes the arm to move up the longer the fall is. However in 1.15 and beyond, I've noticed the arm or camera will not move at all when jumping or falling.
Sorry if this is a duplicate. I searched "View bobbing" and only found issues related to the Pocket Edition of the game, strangely enough.
Duplicate of MC-166387 – no worries about not finding it, since that report doesn't even mention view bobbing 😛