Instant Mining does not reset block breaking. Upon mining with a haste 2 effect applied with a diamond pickaxe with efficiency 5, one will notice that blocks ARE instantly mined, but the block breaking is stopped after just one block. However, doing so with haste 1 will more effectively ALMOST insta mine blocks and do so without stopping after a single block.
Steps to reproduce:
Go to survival world
Give yourself a diamond pickaxe with efficiency 5.
Build a max level beacon nearby a place with lots of stone.
Select the effect as Haste 2.
Begin mining stone.