Some items, when renamed in the anvil, placed in the world and picked back up by the player, their name is gone.

In the attached video, you can see this happens for a bed.

I have tested a few more items, and I don't expect this to work for every single one of them. What I tested:

Items which do retain their name:

• Banner
• Chest
• Shulker box
• Minecart
• Bucket with any fish
• Banner pattern (when used in the loom)
• Music disc (when used in the jukebox)
• Eye of ender (when used to locate the stronghold)

Item which do not retain their name:

• Rail
• Jungle door
• Spruce sign
• Beehive (with and without bees inside)
• Grass block
• Dirt
• Slime block
• Red carpet
• Crafting table
• Rose bush
• Zombie head
• Lantern
• Anvil
• Red tulip
• Blue bed
• Ender chest
• Spruce boat
• Beacon

I think you should be able to rename your bed and beacon and retain their name. Especially the beacon, so you always know whose it is, like people also do with their armor on multiplayer servers. (Chests and shulker boxes do retain their name.)

I also think it is weird that a minecart does retain their name, but a boat does not. These are both quite similar in use. I believe they both should either retain (or not) their name.

For the other items which I tested and don't retain their name, I don't think they need to retain their name. Altough it would be fun if even dirt blocks would retain their name, I don't think this would be intended.