Yes, it does. If you read through the researcher's post, they have an encrypted volume (VeraCrypt-style) which they mount on an otherwise unencrypted filesystem

Yes, it does. If you read through the researcher's post, they have an encrypted volume (VeraCrypt-style) which they mount on an otherwise unencrypted filesystem. Data can leak from inside the encrypted volume, to the cache location outside the encrypted volume. If you're using Filevault2, the entire hard disk is encrypted, including the cache location.