It looks as thought the only thing you changed from the vanilla construction light was to add a custom Addon Node which uses a custom light, is that correct? Otherwise, the nif itself has remained virtually unchanged from the original nif, except for the updated BSValueNode. The vanilla construction light activator also has the BlockPlayerActivation keyword, and I assume it works as it should in game. If that's the case, then there is no need to remove that keyword from your custom light. I've made many custom lights and when the objective is to have the light turn on/off via a connected power source, I always use the BlockPlayerActivation keyword.
The only things I am seeing that might be causing an issue are the name of the BSValueNode not being changed in the NiDefaultObjectPalette, and perhaps the index number you're using for your custom addon node. The name in the object palette shouldn't be an issue, but it seems to me that in the past, not having the name and the AV Object match has caused a problem in one or two of my nifs. As for the addon node index number, you might have another mod installed that uses the same index number and that could be causing a conflict. I checked all the vanilla index numbers and 902 isn't used in the base game or any DLC packs, but since it's so close in sequential order to vanilla index numbers that are being used, I would venture to guess that it was generated by the CK when you created the addon node, and you left it unchanged. Chances are pretty good that another mod you've installed has the same, CK generated index number. Try changing the index number to something that would be a little harder to randomly duplicate in some other mod. Something with 4 digits. I use index numbers in the 5000s and have never had a conflict.
Hope this helps.