It is possible that you are initially dropping data packets on the wifi, even with a "strong" signal. This can be caused by radio interference from somewhere or something blocking the "line of sight" between the two points. This could be a refrigator, metal ductwork, electrical conduit/lines in the wall, pipes, metal studs in the walls, etc.
Once the handshakes between the wifi source and the receiver are completed, the system should adjust the packet size to keep optimize the data integrity, if needed. Thus, you have a slow start, and then it evens out. A great example of this is when watching TV over wifi and you see then resolution go up or down after a few seconds.
(Making a few assumptions: you have a typical home networking setup, the Nucleus is plugged into your wifi router or a network switch which is hardwired to the wifi router, and all the equipment is working properly.)
There are a couple of simple tests you can perform to see if you can get an improvement and/or start diagnosing the problem. First, power everything down (modem/router, network switches if present, Nucleus One, streamer(s), TV's and any other heavy wifi using devices). Then after say 10 minutes, restart, beginning with the modem/router, ending with the streamer. (If your modem and wifi router are separate, make sure the modem is fully up and running before starting the router.)
If that solves the problem, great! If not my next step would to change the "line of sight" of the wifi signal. Not knowing where your wifi router is in the house, and what is between the router and receiver, try moving the wifi router at least 10 feet in a direction parallel to the streamer and power cycle the streamer. If it is better then something is causing signal interference. If no improvement, then there are some additional diagostical steps that you can take. But I would start with these two.
-Jeff
(33 years as a computer systems administrator, network administrator, and IT Manager for a multinational manufacturing company)