Not to dissuade you from Unibond, but my understanding is it is not completely free of water. Some of the water typically used in uf glue is replaced by furfuryl alcohol.

Some years back, I was running two vacuum presses off a manifold. Turned one press off to load the other, and neglected to turn the first back on after the second had achieved vacuum. The first one had a 4 piece burl match glued with Unibond, and during the hour or so before I realized my mistake and reapplied vacuum to it the veneer joints opened up at the periphery. Although the pressure was reapplied soon enough that the veneer bonded to the substrate, the moisture in the adhesive caused the joints to open up during the period of low pressure and made the panel unusable for the job (my coworker cut it down and used some filler to make a marginally acceptable coffee table top).The point being that whatever liquid is in Unibond has the ability to expand wood cells.

I have used Unibond numerous times without issues, but some people have had problems with insufficiently mixed batches causing staining in light colored veneers like maple or English sycamore. That is the reason for the instructions calling for mixing, allowing it to rest for several minutes, then mixing again. There is a thread on the topic on the Woodweb forum. I don't know if this is still a potential issue with the newest formulation, but it's something to be aware of.