Could you share your configuration for link aggregation? I did it for a while but if I remember correctly, while plugging the cable into my laptop worked as expected I think that in order to get connected to wifi again after unplugging the cable, I had to manually

    service restart netif lagg0

And sometimes also

    service restart dhclient lagg0

But it might also be that I was to impatient and that it would have reconnected to wifi by itself if I gave it more time. How long does yours take to get back on wifi?