sonos sirq ksoftirqd merlin asus rt-ac68u

I have a very weird problem on my RT-AC68u running merlin 380.69. This happened in 380.68_4 as well, I thought upgrading might fix it but no luck. The weird part is this problem only occurs when I have my Sonos Play:1 connected via 2.4Ghz wifi! With the Sonos connected, I get ksoftirqd...