Hanging signs aren't rendered when held by endermen or as block display entities

The Bug

Hanging signs don't render when an enderman is holding them or as block display entities.

Reproduce

/summon minecraft:enderman ~ ~ ~ {NoAI:1,carriedBlockState:{Name:"oak_hanging_sign"}}

/summon minecraft:block_display ~ ~ ~ {block_state:{Name:"minecraft:oak_hanging_sign"}}

Observed Result

The hanging sign didn't render when the Enderman held it, or when it's summoned as a block display entity.

Expected Result

The hanging sign would render.