The banners and shields with banners They cause lag, when the player takes, creates and equips one of the mentioned items.
It doesn't matter if they have a pattern or not, simply when you have them in your hand or in your inventory, the game lags.

Steps for Banners (With/Without Patterns):

1. Take a banner with or without a pattern from crafting or creative inventory.
2. Equip main hand.

Expectations:
When equipping in the main hand, the game should be smooth.

Observed Results:
When taking and equipping a banner in your main hand the game takes a while to run, causing lag and gameplay issues.

Something similar also happens when the banner recipe is unlocked, since the game icon apparently freezes. (Possible issue with banner rendering in HUD and inventory)

Steps for Shield banner (With/Without Patterns):

1. take a shield from survival crafting or creative inventory.
2. take a banner With or not Patterns and place on crafting grid.

Expectations:
Creating a banner shield should not cause the game to suffer any performance changes.

Observed
-When creating a shield with a banner, the game takes time to create the item, also when equipping the shield in the main hand or offhand. (This could mean a problem with the item's rendering). This is also related to enchanted shields (possible issue with shield rendering).

android device that experienced this problem: Moto g8 Power Lite, android 10, RAM 4GB, Processor PowerVR Rogue GE8320