Mastery orbs can be applied to same slot if network lagged
I find I lost 2 mastery orbs since there are 11 empty slot in my mastery tree but there are only 9 orbs which haven't be gotten.
Fortunately I think I partially know how it happen.
I remember when I bought the advanced mastery, I got a lot of orbs. But at that time, my network seems not stable so I remember I couldn't lighten one of the slot, and I tried to lighten that slot for many times. I think my orbs lost at that time.
It probably caused because my orbs was consumed on the server side, but client didn't receive the result so the slot on client side is still dark, so client can still lighten that slot which server thought it is already on. Somehow server didn't check the slot status and still consumed the orb. Then my orb lost, because some orbs are consumed on the same slot.
I think this issue is better to ask engineer about the program logic
I'm not sure if the reproduce steps works since it related to network:
1. Using a laggy network to start the game, the account needs to have a lot of orbs to use.
2. Use those orbs to lighten mastery tree, some times you will find one of the slot can't be lighten.
3. Try lighten that slot again, probably at that time, you consumed 2 orbs but only lighten one slot.
PC, windows 10
Lost 2 mastery orbs.
I should have 2 unused orbs.