@Jeffg53 
Yes, I just check on the support section for the switches, no firmware to be found, perhaps you can zero it in down on the Decos firmware, as you've said, you never face this issues before back a while ago.

If moisture is a potential problem, highly suggest that you take it back in to the store from where you got it and have them to ask for its warranty if its possible for you to exchange for a new one or get it fixed.

Decos are not IP rated unless is a outdoor rated one.

  @Omochao when I was first getting backhaul set up, I was told by Deco support that it would not work in access point mode. I have been using router mode since then. I just thought that I would try ap again and it worked immediately. Now I am totally confused, but very happy to have backhaul working again. 
 

Thanks for your help. I hope that Deco support read these threads. 

  @Omochao I have just had a livechat with Deco tech support. They told me that AP is correct for my setup. There are a few questions in my mind but I am very happy to be working again. Thanks again.