Crystallization is a result of the epoxy resin evaporating some of the solvents out and attracting moisture. There is no way to know how old the epoxy was prior to being bottled and no way to know how long it sat on the shelf prior to even getting shipped to the end user. The result is an epoxy that will never completely crosslink correctly. Bottom line is that it will not be as strong as fresh epoxy. Impossible to say if that will create you issues or not. I gave up on hobby grade 1:1 epoxy systems long ago. I keep a quart kit of laminating epoxy resin around at all times with several different hardeners that allow me to choose the cure time that works best for the job at hand. In order to make up a paste adhesive, just add milled fiber and Cabosil until you get the consistency desired. The end result is much stronger then hobby grade epoxy.