Comment 5 for bug 1490347

So what happens here is that the authentications fails with a MGMT_STATUS_AUTH_FAILED error code. Because of this bluez retries the authentication multiple times. That is why you get the multiple PIN code requests in a row.

Can you please elaborate a bit more on the exact steps you do? Please also include which keys/buttons you press on the keyboard and if the keyboard. Also from which year is this apple keyboard?