Cannot Change Entity Variables?

This has happened to me on a few occasions where I cannot change entity variables?  They have a access_id of 2 but if I do for example:

$skill = get_entity(234235);
$skill->stage = 1;

//Skills stage variable was initially 9

echo $skill->stage;

It will echo 9.  Cannot change it at all.  Why does Elgg randomly "protect" variables for some reason and how do I fix this?  Getting sick of not being able to edit variables randomly.  Ps.  If I were to create a new "Skill" entity, as seen above, I'd be able to change the "stage" variable as much as I want.  JUst seems to affect previously created entities or something...