Sometimes the save method takes an admin user as current user

[Guido1982]

I frequently use the 'save' CRMEntity method to alter records through AJAX calls. This way we can easily track (through the 'view history' button) who did what at what time. I also use it in my custom webservice methods. No harm there, but sometimes the user swtiches to myself (because I am the first available admin user). This seemd to be regardless of the user doing the actual change: sometimes the user stays intact, sometimes it changes, even though he is on the same profile as other users, where this does not happen. Am I missing some rights management here?