Probably channel related.

For those that might be reading this with similar issues. I've found they can be fickly with wifi connection. You have to position them right to have a decent connection, at least a stable one. Any metal, walls or large items could potentially interfere with the signal because the hardware responsible for the wifi on the board is so small. This goes for Bitaxe's and Nerdqaxe's.

Another thing, is if you've got a fairly congested 2.4ghz network it can cause problems, as well as a "smart" switch on the channels. It might be worth downloading a wifi analyser (ideally open source) and checking which channels are performing the best, and switching to manual channel selection to prevent it from switching non optimally to another channel which could cause down time.

I also think the devices just aren't all that good at this due to the small wifi hardware. I still despite averaging around 24ms ping from the miner itself have spikes into the 80-120ms. Testing the ping from my computer to the router I get a very stable 1/2ms.