Here's the definition of "observe": notice or perceive (something) and register it as being significant. Unliving matter doesn't perceive anything.
The back board is not what scientists are talking about when they refer to the "double experiment observer effect." They are talking about the measuring device in front of the two-slit board.
The back board records whether the photons are being observed (measured and perceived by intelligent humans) prior to passing through the second slit. The back board tells us whether somebody was watching (i.e. measuring) the photons.
Set up the measuring device. Turn it on, and the back board shows the two bars. Turn off that device, and the same board gets the waves-interfering "possibilities" reality.
Where in there are we miscommunicating? What do you regard as the "observer effect", the one which is caused by the on-off switch on the man-made device?
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But I do think we're edging closer to having our site linked by Bing under "double slit experiment debunked" attempts ....