Minecraft 24w09a changelog says that blurred background is not applied to container blocks. However some blocks and entities do use a blur as a background texture, this includes:
Command blocks
Jigsaw blocks
Structure blocks
Command block minecarts
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Thank you for your report!
After consideration, the issue is being closed as Working as Intended.
Please note, that mechanics of the game may change between updates.
Things such as graphics, sounds, world creation, biomes, redstone, villagers, and animals may not work the same in current versions.
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