The x86 platform with Patch id 4277 installed and locked domain files are not encrypted.
I am attaching sequence of  commands to test FS encryption. After the domain is locked i am still able to read the 
content of the file in that domain. My quess is that the sequence of event  of my test is not correct. 
The sequence of  command is listed below:
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# fdisk /dev/hd1 add -t 178 -p 100
# mount  -e /dev/hd1
# mkqnx6fs -E /dev/hd1t178
mkqnx6fs: filesystem block size must be 4k when file data encryption is enabled
# mkqnx6fs -E -b 4096 /dev/hd1t178
All files on /dev/hd1t178 will be lost!
Confirm filesystem re-format (y) or (n): y
Format fs-qnx6: 3863620 blocks, 120768 inodes, 8 groups
# mount -vvvv -t qnx6 -ocrypto=enable /dev/hd1t178  /enc2
Parsed: mount from [/dev/hd1t178] mount on [/enc2] type [qnx6]
exec: mount_qnx6 -o crypto=enable /dev/hd1t178 /enc2
Using internal mount (mount_qnx6 not found)
Type    [qnx6] Flags 0x00000000
Device  [/dev/hd1t178] Directory [/enc2]
Options [crypto=enable]
# fsencrypt -vv -c check -p /enc1
Logging verbosity set to 2
# fsencrypt -vv -c check -p /enc2
Logging verbosity set to 2
ENCRYPTION_CHECK(Path:'/enc2') INTERNAL NOTICE: (12) - 'Supported'
# fsencrypt -vv -c create -r -t1 -d20 -p/enc2 -k+password
Logging verbosity set to 2
CREATE_DOMAIN(Path:'/enc2', Domain:20, Type:1) SUCCESS
UNLOCK_DOMAIN(Path:'/enc2', Domain:20) SUCCESS
OK
# touch /enc2/test1
# touch /enc2/test2
# fsencrypt -vv -c setup -k:20:1:0::/enc2
Logging verbosity set to 2
SUCCESS
# touch /enc2/test3
# echo "test4" > /enc2/test4
# fsencrypt -vv -c lock -d20 -p/enc2
Logging verbosity set to 2
LOCK_DOMAIN(Path:'/enc2', Domain:20) SUCCESS
# cat /enc2/test
test1  test2  test3  test4
# cat /enc2/test4
test4
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Please advice 
Janusz