Opening external applications (classic confinement)

It seems that the evince program has loaded the library provided in the snap and thus try to do things with in-snap behavior, this configuration is NOT supported. You have to modify your application to drop all the snap entries in LD_LIBRARY_PATH before trying to call any external programs that are not in the snap to prevent them loading the wrong libraries, refer Subtle differences between devmode and classic confinement snaps for more details.