The auto-decon is not functioning. I disabled and reenabled the mod, no change.
It was working earlier, not sure what changed.
~ I do have the setting enabled, I toggled it repeatedly.

More specifically, it only works on some entities, and not others. Its working on things in one area, and not those in another area.

So far as I can tell, The line
local areaList = builder.surface.find_entities_filtered{area=searchArea, force=builder.force, limit=40}

Doesn't work correctly, unless you remove the force=build.force
Not sure why. This also makes it work on trees, but it now works always.

Hmm. Looks like a mod compatability issue. Not sure what could cause an issue so bad that your player doesn't consider itself on the same force as what you placed...

https://mods.factorio.com/mods/Nexela/PickerExtended/discussion/new

Not sure why, but if this mod is installed it doesn't work. Not sure why.

If you change limit=40 to something higher then it will work but only if there are less entities in the players reach distance than the limit amount. With the LongReach mod you have to boost this number to something really high (I have mine set to 4000.) For performance reasons you should choose the minimum amount needed for the mod to work, as once you stand still it will be constantly looking through the entities for ones that need to be deconstructed and could lead to a drop in FPS/UPS.

That worked, thanks. This was driving me mad.

I just set it to 4000, and just turn autodemo off until I use it. Good idea anyway.

Ba-da-bump. Still not working.

PickerExtended is also an (optional) dependency of Nixie Tubes, which I didn't realise until I found this thread. I've disabled it and restarted the game, no deconstruction at all. Construction works very well. I'll toggle a few more mods.

EDIT:

As it turns out, the Long Reach mod appears to be breaking auto deconstruct.
Isn't that wild?

EDIT 2:
Guess who didn't read the entire thread?