The Bug:

You cannot see other players on maps.

The 24w39a changelog states that 

Equipping a Carved Pumpkin on your head now removes the player marker from other players' maps

however, player markers cannot be seen on maps to begin with. Tested in a LAN world.

Steps to Reproduce:

1. Get two players and label them "Player A" and "Player B".
2. Get "Player A" to fill a map and have "Player B" stand close by.
3. Get "Player A" to look at the map and see if they can see the player marker of "Player B".

Observed Behavior:

You cannot see other players on maps.

Expected Behavior:

You would be able to see other players on maps.