When using pressure mounted adhesives, the main thing to remember is that the larger your piece, the more chance it will release somewhere. The main problem is that there is a limit to the shear strength of the adhesive and when the paper and/or mounting substrate moves due to expansion/contraction, it is testing the limits of that shear strength.
3M's PMA..positional mounting adhesive... is good for only up to around 24" or so, so if you have a print of around 20x24, you are pushing the limits of the adhesive to keep it down flat.
Remember that even tho you are trying to use an adhesive that is "acid free" so the acids don't damage the paper, there are other things in the adhesive that can damage it as well. Numerous chemicals that make up the adhesive will migrate to the paper and cause damage. What this means is that any chemical based adhesive will, by its very makeup, not be archival.
On the other hand, if you are old enough, you can use the "bad stuff" and still offer a life time guarantee for your work and be pretty much assured that it will not visibly degrade till after you are dead.