CKEditor filtered HTML body field is not showing for non-administrator users when editing
The commonest reason for this problem (and OP has confirmed it in this case) is as follows.


The field that is inaccessible to some users has a filtered text format
The formats that can be set on that field include one or more that are not permitted to all users (typically "full html")
The content item in question has been edited by a user that has access to the restricted format and they have saved it with the field set to that format.
Now only users that have that privilege can edit the item because that field won't load for those who don't.


The solution is for a privileged user to edit the item and change the format and save it again, though that may result in the HTML changing in a way that's undesirable. If the item needs "special" HTML then it may not be possible for it to be maintained by the less privileged users.