Steps to reproduce:
1. Give yourself a diamond sword, for example.
2. Use "/enchant @p unbreaking" to enchant it with Unbreaking I.
3. Now use "/enchant @p unbreaking 3" to enchant it with Unbreaking III.
Expected result:
It should just upgrade Unbreaking I to Unbreaking III. You can combine Unbreaking I with Unbreaking III on anvils, /enchant should be able to do it too.
Actual result:
"Unbreaking III can't be combined with Unbreaking I"
Linked issues
is duplicated by 5
MC-113331
Can't combine enchants with /enchant command
Resolved
MC-237019
You cannot increase the tier of enchantments on items when using the /enchant command
Resolved
MC-244184
/enchant doesn't work on already enchanted items with the same enchant already applied
Resolved
MC-271421
enchant command can't re-enchant item with higher level
Resolved
MC-273151
Using /enchant command sometimes results in an incorrect error message
Resolved
That would explain the weird behavior of the enchantments table, despite having 30 levels and choosing a 30 level enchant, the results are always a mix of low level enchants on everything I've tried so far, max unbreaking level I got is 1, max level of Fortune and Looting is also 1, can't go higher also on all other enchants, the only ones that seems to work is Thorns.