Lockbox drop rate bug

[MalippeW]

Date & Time: 05/29/2021
Frequency: At each skirmish
World name : Moogle
Character name: Malippe Wilerck
Class/Level: Warrior / 80
In-game time: at any time
Area and coordinates: Bozja and zadnor maps

Steps:
1. When i do skirmishes on bozja and zadnor skirmish i don't get a lockbox everytime (even with gold rating), it used to so but since yesterday the drop rate is random
2. here the screenshot for exemple

https://i.imgur.com/EbKhxsm.png
https://i.imgur.com/IXk9Q1J.png