Users log in and see other users registration details

Hi,

We have a wordpress site which has been customised and works as a job board. We recently introduced mandatory registrations before a user is allowed to apply for a job.

We also installed clicktale on the server so we could see samples of user behavoiur on the site.

We noticed that some users were logging in and instead of seeing their own details, they were shown my details – a test profile that I created last year. This seems to happen with alarming frquency and our developers cant replicate the issue, though we know it is an issue, having seen it through Clicktale and also users have sent support emails.

Is this is a known bug anywhere, and can someone please help us?

Thanks in advance