When enchanting items, the enchantment table doesn't change the enchants. For example..I wanted to enchant my diamond pickaxe. The level 30 enchant was for efficiency 2. I didn't want that. So I used a level 1 enchant on a stone pick. Went to enchant diamond again and they were all the same enchants.
MC-99149
1.9 Enchantment Table not cycling
Resolved
Invalid
0
There is some randomness involved. It is possible for the 3 shown enchants to be the same for two different seeds.