Custom entity spawn eggs are not visible in the creative menu for players connected through multiplayer.

Partner Rank: 1

Verification builds:
1.16.200.02_rc2  - R16 Update 2
1.16.201.01_rc0 - R16 Update 2 Hotfix 1
1.16.210.58 - R16 Update 4 Beta

Impact:

This may have a major effect on reviews, players are unable to play the map correctly.
Custom entity spawn eggs are not visible in the creative menu for players connected through multiplayer.

The following Noxcrew content is affected by this bug:
Millionaire Mansions 2
Future Noxcrew Map

Repro Steps:
Download Millionaire Mansions 2 from the Marketplace store
Start the map and invite a second Minecraft client.
Open the creative menu on the second client and navigate to the Spawn eggs
Navigate to the Custom entity Wooden Chair

Observed Results:
Custom entity spawn eggs are not visible in the creative menu.

Expected Results:
Custom entity spawn eggs are visible in the creative menu.

Screenshots/Videos attached: Yes

Regression Build:
Yes, Custom entity spawn eggs are not visible in the creative menu for the second connected player in multiplayer on version 1.16.100.54_rc0