Named maps in containers show as 'Unknown Map'

The equivalent bug on Java is MC-157590

At least in 1.16.40 (Xbox), the one exception is if the map stored in the shulker box is applicable to the currently-loaded chunk. That map will display its name when you hover over it; any other map in the box that has not yet been viewed by the user by transferring it to their inventory will appear as unknown.

This can be reproduced using chests as well. Also affects 1.16.201.

I can confirm this happens to un-custom-named maps as well. 1.17.10 

This just happened to me. I played a world I haven't played in a little while. It was last played before the recent update (PS4). My map had been stored in a chest and I noticed it said "unknown map". Curious I selected it and tried to put it in my personal inventory and the whole game crashed kicking me out to the PlayStation menu. So not only is my map useless now, if anyone touches it the game fails. Please fix!

I am reproducing this as well. Viewing the map will temporarily restore the name sometimes. Breaking the map out of a frame will reset the name sometimes.

Here is all I know about it, if it's helpful; it's just a copy of a duplicate report I filed earlier today. Some of this might not be right:

Sometimes, when a named map is placed in a chest, returning to the chest later shows the map name as "Unknown Map".

I am yet unable to determine the steps to reproduce this consistently, however here is what I know (or think I know):

• The name is not permanently changed; it returns to its correct name when the map is moved into inventory. Also, the map contents are not lost, no issue there.

• The name is always displayed correctly when initially dropped into the chest. It is only when returning to the chest later that it changes to "Unknown Map".

• It doesn't happen to every map, sometimes it only happens to a few maps in a chest. It seems related to whether the map is in use or not. In particular, I've seen the following so far:

  • I've never seen it happen to a map with a clone in my inventory.

  • I've never seen it happen to a map with a clone in an item frame near the chest.  

  • I've seen it happen to a map with no clones outside the chest.

  • I've seen it happen to a map with a clone in an item frame that was in a far away chunk from the chest.

• It doesn't happen immediately. Sometimes returning to the chest shows the correct name, then later it changes to "Unknown Map". So it might be related to distance walked from the chest - I tend to notice it after returning from a long journey. Otoh it could be related to quitting the game and returning. Unable to determine yet.

• I've never seen it correct itself on its own, it always requires moving the map back into inventory.

The consequence is it is very difficult to determine which map you are removing from a chest. In cases where multiple maps are affected, including the one you are looking for, you must move each map to your inventory in turn to see its name in order to find the one you want. It is not a major consequence, but it is inconvenient.

I will post here if I notice anything else.

 This is still an issue in the latest versions of 1.21.