Anvils take damage even when falling only one block. They could only take damage when falling more than one block in 1.16.5.
To reproduce
Build a pillar
Put an anvil on top of the pillar
Break the blocks of the pillar one at a time from top to bottom, to let the anvil fall down
→ ❌ Observe the anvil taking damage as the process goes on
Can confirm. This didn't happen in 1.16.5.