bummer the project had problems for you. I use tighbond all the time. 1 for veneer ironing and just about everything else. type 3 for waterproof stuff, never on veneer.

MY guess is not enought glue or the oil you put on. I like to put on a good coat and let it tack over. I dont wait for the glue to dry. some people wait. I use two coats of glue. Depending on the veneer the application varies.

For raw veneer I put one coat on the substrate, let is dry so you can touch it, then put another coat on top of it. you have a wild animal loose in your shop if you put something wet on raw veneer!

For paperbacked veneer. I put one coat on the substrate and one coat on the veneer. I have yet to see this curl paperback veneer more than a wisker.

I like the glue to get tacky but not dry. If its too wet you get too much moisture into your project. work the iron carfully and I would guees the time frame for the side of a cabinet 14" x 30" to take about 20 minutes. too much heat will crack your veneer and can actually cure the glue too fast while the veneer isnt even in contact. you have to work it slowely and massage into place. The veneer does'nt want to be there all glued down. you have to coax it into the situation.

If you gently tap and the tips of your fingernails on the veneer you can hear when the veneer is not bonded. That's why you saw that little 300B amp in my shop. Cant let the music be too loud or you cant hear the air bubble! I really think your problem was from a dry spot in the glue. Maybe try a cheap roller next time. I use an ink roller, hard rubber with no nap. it works well. I used by mistake or chance 10 years ago and it's always done well.

I cant see the oil doing anything to Paper veneer but maybe soak through raw veneer and disrupting a partial bond. I really dont know. I do know its always chancy to do anything before your 24 hour cure time has passed. We all do it, but it's russian rulette.

more glue coverage
gentle, steady and lengthy ironing
low to med heat
fingernails