Banner in Off-Hand Appears as an Oak Sign in First-Person View

Short description of the issue:

A banner held in the off-hand appears as an oak sign in first-person view.

Steps to reproduce the issue:

1. Open a Minecraft Bedrock Edition world with cheats enabled.

2. Use the /replaceitem command to place a banner in the off-hand slot.

3. Switch to or remain in first-person view.

4. Observe the banner in the off-hand.

Expected result:

The banner should appear correctly as a banner in first-person view.

Actual result:

The banner appears as an oak sign in first-person view.