How I discovered the issue:
I was trying to create a system that counted how many blocks are farmed by players throughout the play-through of a map. My idea for this system was simple, when a block is broken, tag the entity form of the block before it is picked up, then add 1 to the scoreboard. That way, it's considered different from other entities and therefore, players can't just drop the item to increase the score value. However, when the item is picked up, it appears that any tags that were applied to the item are gone.

How the system would have worked:
Repeat Command Block | Unconditional | Always Active
/execute @e[type=item,name="Oak Log"] ~ ~ ~ tag @e[type=item,name="Oak Log",r=1] add countedoaklog

• This basically executes a command for all broken oak logs to apply a tag to them called "countedoaklog" so it is considered different from other oak log entities.

Chain Command Block | Conditional | Always Active
/scoreboard players add "logs" Resources 1

• This basically would add 1 into the scoreboard if the tag was applied. "logs" is not a username and is instead a randomly added placeholder or "player".

Steps to reproduce:

1. Drop any item into the world.
2. Execute a command to tag the item.
3. Pick the item up.
   All added tags are removed.
   You can test this by dropping the item again and trying to kill all entities with the tag you added.

I was not sure if this is considered a "bug" or an intended feature. If I could receive clarification on this, it would be much helpful and if you could provide a solution to my problem, I'd be more than grateful.