What happened
Replace offhand item using /replaceitem while opening GUI cause that item not being render properly, until

• Press F key, or
• Re-enter the world

GUI included:

• shulker box (included colored ones)
• chests (ender, trapped, regular/with minecart)
• anvil
• tables (crafting, enchanting, cartography)
• brewing stand
• furnace ( with minecart, blast)
• beacon
• dispenser/droper
• hopper/with minecart
• villager trade interface
• creative inventory (Click "E", in any tab, "Building Blocks", "Decoration Blocks", "Redstone"..., except the bottom right "Survival Inventory")
• lectern
• stonecutter
• grindstone
• loom
• barrel
• smoker

GUI Not included:

• survival inventory

How to reproduce:

1. Place a crafting table.
2. Place a command block with the following command.

   /replaceitem entity @a weapon.offhand minecraft:diamond_sword 1
   

3. Connect with redstone repeater so you will have enough to open GUI in time.
4. Hold any item other than the one in the command above.
5. Place a redstone block, and right click crafting table before the command block get powered.