Inconsisent behavior with entity_metadata_wrapper

This module has some tricky unintended inconsistent behavior with entity_metadata_wrapper.

Conveniently when you load a entity with an encrypted field, it will give you the unencrypted
value. Likewise, when you set and save a value on that field programmatically you don't need to encrypt it first.

$my_entity = entity_load($entity_id);
$my_entity_wrapper = entity_metadata_wrapper('some_entity', $my_entity);
$value = $my_entity_wrapper->field_encrypted->value();
//yay $value is decrypted for us!
$my_entity_wrapper->field_encrypted->set("Some unencrypted string");
//new value automatically encrypted

However, if you save the wrapper at some point, the values go back to their encrypted stat:

$my_entity = entity_load($entity_id);
$my_entity_wrapper = entity_metadata_wrapper('some_entity', $my_entity);
$my_entity_wrapper->field_encrypted->set("New value");

$my_entity_wrapper->save();
//Oh noes!! We saved. The value below now is encrypted :-(
print $my_entity_wrapper->field_encrypted->value();