inconsistent pick up of items that drop from blocks under players feet

I think it Works as Intended since yes, you can pick up items from some distance but the item flies away from you in this case, making it hard to pick it up

That's not what the report is about though. The issue is that the behavior is inconsistent. It's not a question of why the block is not picked up, because that is not always what happens.

I highly doubt this behavior is intentional/a conscious decision by Mojang. 

Items cannot be picked up immediately after they spawn. By the time they can be picked up, the items have fallen too far.

I dont think anyone is questioning how the current behaviour works.

They are questioning the inconsistency of the behaviour - and whether that is intentional or not

There is no inconsistency

There is inconsistency. Sometimes, you will be able to pick up the falling block.

After some further testing, I believe the inconsistent behavior may be the result of lag/lagspikes.
I can see how the game failing to sufficiently simulate the block moving away from the player in time before the item drop pickup timer runs out, could result in the player ending up picking up the falling block.

Set up a command with

execute as @e[type=item,nbt={PickupDelay:0}] run data merge entity @s {Motion:[0d,0d,0d],NoGravity:1b,Glowing:1b}

Then break some blocks on a bridge and observe where they end up. Due to the random motion, some are too low to pick up, some aren't. Nothing to do with lag.

typically the player picks up items within 1m of the players bounding box but this doesnt seem to work 1m below the player