In my ongoing effort to ask every basic woodworking question possible, I
submit the following puzzler:

I glued up another bookcase last night. Again it was 5 shelves in
dadoes, made of ply that I had prefinished with the mating parts masked
off. I glued up the unit face down on a work surface whose strategic
areas were covered with shiny packing tape.

I had discovered on the previous unit that I could easily remove the
squeeze-out that collected in the corners where the shelves, uprights
and work surface meet the next morning, so I didn't bother with those
areas last night. Several such corners had healthy amounts of glue that
collected there due to pressure and gravity.

Upon checking the progress this morning, those glue blobs were gone. Did
they wick back into the plywood edges somehow? I removed the clamps and
lifted the unit up, putting it on its side with the front of the unit
facing me. These "front" edges were the ones that were previously laying
on the work surface. Sure enough, there were a couple of places where I
had to scrape off glue that had squeezed out of the joints, but those
corner blobs were nowhere to be found.