Blocks mined just before death have respawned, happened on two occasions.

First time was approximately 100-200 block along z axis in the nether at level y=15. Died from kinetic energy. Entire row respawned. 

Second time remining the same blocks final four of the "first respawned" ones, lava death from mining a block on the x axis but upon arrival back those four blocks  done just before death had respawned. 

The blocks respawned in same configuration and reloaded the same types (netherack, basalt, backstone and ancient debris) 

These blocks were duplicated in the inventory and so got double from the same area due to the respawning.