Could you elaborate on this in more detail?
Are you saying that when the WiFi scan is completed and you try to connect to the access point - it connects, disconnects and only then it connects normally?
In this case, it's all good, this is how it's supposed to be as both devices have to handshake to confirm that the information about the access point is correct, when the check is done it connects normally.
When connecting through smartphones, for example, you will get a half a second "No internet" message on the device before it connects normally to the network, so in this case, it's the same, maybe it just takes longer as the device is not that powerful to do this quicker.
Sometimes it's quicker and you won't notice the status change.