For sake of discussion... Let's be clear about some terminology... A block inserted into the drawing is called a 'block reference'... when you are editing or building the block in 'bedit', you are editing or creating the 'block definition'...
to bucksurfboards... did you add the field pointing to 'Value' of an Attrubute Definition in the block editor? If so, then... I think I still have an issue...
... mine started working after I added... or should I say added a second time the field... but ONLY after the block reference was inserted into the model. I had to add the field pointing to the attribute from the block reference. It seemed the adding of the field pointing to an attribute definition within the block editor either is not necessary. I am still experimenting with this.
one thing I am puzzled about though... Charles said "There cannot be any Default value in the Attrib. This needs to be left blank when creating except for the Field being chosen." ... I am assuming that you mean that when editing the 'block definition' you need to place the field into the attribute definition's default value.
To get mine to work when actually used... I think I would have to have the block actually inserted in a dwg in our block library with the field in place on the block reference, then explode it on insert... but then it would have to be copied or inserted from our library when another is needed.
See mine attached...