While 68 cm is very unusual and certainly I think there are some other untypical features from the Y litter, I guess it's not totally impossible to believe Issar's genetics could have contributed to the height. These dogs, also coming from the lines of Ada Kollorav Dvor, also had unusually (at least to me) tall height:
http://www.wolfdog.org/dbase/d/7446
http://www.wolfdog.org/dbase/d/9857
http://www.wolfdog.org/dbase/d/5187
http://www.wolfdog.org/dbase/d/1919
http://www.wolfdog.org/dbase/d/1339