Switching from holding a weapon to holding nothing or vice-versa then quickly breaking a block desyncs the sound, particles of breaking, and dropping the items.

Steps to Reproduce:

Behavior #1:

1. Hold something other than a sword in your main-hand, and a sword in your off-hand
2. Press the 'Attack/Destroy' button and 'F' to swap hands at the same time
   → The block break particles will show, the break sound will play, but the block will not actually be broken and will quickly reappear.

Behavior #2:

1. Hold a sword in your main-hand, and something other than a sword in your off-hand
2. Press the 'Attack/Destroy' button and 'F' at the same time
   → The block break particles do not show, the break sound will not play, and the block will vanish.

Expected Results:

The behavior of the block breaking would respect whichever item was held in the player's hand when the initially broke the block.

Video/s:

MC-186770 block desync.mp4