General answer (as my expert knowledge is AIX EFS, not linux)
When talking about encrypted files - you must distinguish between 'stored' and 'in memory'. What I expect you are experiencing is that the file contents are 'in memory' in clear text - while (I am sure) they are encrypted 'on disk aka stored' or also called - 'at rest'.
Test for you to perform:
* as non-root userA add a file to your encrypted filesystem, mode 644
* as non-root userB - you are not expected to know the encryption key, so ideally you cannot see the 'clear text', better is no access.
* as root, ideally, no access (without decryption key), worst case, can see the encrypted data.
On AIX, so I shall assume that Linux is the same: you will need to have some credentials that allow you to access (the secret key used to encrypt/decrypt) the 'at rest' data and/or access cached representation of same 'in cached memory' data - above and beyond the traditional *NIX DAC access mechanisms.
However, my assumption may be wrong. If Linux is doing encryption per partition rather than per file - having access to the encrypted partition could imply that the only remaining protection is by the classic DAC and/or ACL mechanisms (e.g., extras coming via SELinux and/or AppArmor)