If you add a banner to a shield, the shield will show the banner in your hand and when dropped, but not when it is in your inventory (hotbar or otherwise). This seems to affect every banner pattern.
MC-272400
Shield in Inventory with Banner Shows as White
Resolved
Fixed
2
I can confirm that this is an issue. Further I am not affected by MC-272365 in 24w21b but I am affected by this so I believe this and MC-272365 are separate issues