This is not unusual nor is it normally a problem. The mesh is managed by moving devices from node to node as they move about or as the network conditions change (load, aggregation of clients on one node etc). Your assumption that clients connect to the nearest disc is not correct as the network is smarter than that.
Are you having performance problems with any of the devices ? If not take John Lennon's advice and let it be :-)
You could go to your wifi adapter properties and play about with the roaming agressiveness settings. This may make a difference (probably not), but maybe still worth a try
There is a fix for the Intel compatibility issue coming next week so that should help your situation.
What sort of signal are you picking up from the wrong disc? Anything above -70 will give you a good connection speed anyway. Sometimes Whole Home will try to move your device to the closer disc but your device will ignore it.