Unity NM coffer not always giving rewards

Platform: Windows
ISP: Comast
Type of Internet Connection: CATV
Internet Connection Speed: ~
Date & Time: 2016-08-15
Frequency: 4-5 times
Character Name: Muirago
Race: HumeM
World: Asura
Main Job: RDM, Lv.99
Support Job: DNC
Area and Coordinates: Windurst Walls, AH
Party or Solo: Solo
NPC Name: NA
Monster Name: NA
Steps:
- Obtain unity NM coffers (Bounding Belinda in my case)
- Assert related rare items are NOT in your inventory
- Open coffer a few times
- Observe half or more of the time the coffer does not produce results / items (used to always be a 1 to 1 ratio of reward to opening)
- Observe coffer does still provide a gil reward the rest of the time