I have included 3 pictures here where it can be seen that in my Festers the damage are above 800 (normal damage not critical). For normal damage of 800 that's a 3 DOT Fester. I believe that this also happens in Labyrinth of the Ancients.

Time: 16/07/2014 17:00-17:30 GMT+8
Frequency: Always during the fight
World name: Chocobo
Character name: Nina Miqotra
NPC name: n/a
Monster name: Scylla, Glasya Labolas, Amon, Xande
Class/Level: Summoner LV50
Party or solo: Party
In-game time: n/a
Area and coordinates: Syrcus Tower

Steps:
1. After starting the fight with the bosses apply Bio II, Miasma and Bio.
2. In the middle of the fight the DOTs suddenly disappears before the time.

Connection Specs
- Type of internet connection/provider: DSL(PPPoE) / CTM

PC Specs
-=-=-=-=-=-=- System Information -=-=-=-=-=-=-

SYSTEM_OS Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.140303-2144)
SYSTEM_CPU Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz (8 CPUs), ~3.4GHz
SYSTEM_CORE_NUM SYSTEM_CORE_LOGIC 8 SYSTEM_CORE_PHYSICS 4
SYSTEM_BIOS BIOS Date: 11/09/12 11:39:37 Ver: 36.03
SYSTEM_LANGUAGE português (Regional Setting: português)
SYSTEM_MEMORY 4063.141MB
SYSTEM_VIRTUAL_MEMORY 2047.875MB
SYSTEM_PAGE_FILE 8124.461MB
SYSTEM_STORAGE C:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 238.473GB SYSTEM_FREEDISC_SPACE 162.582GB
SYSTEM_STORAGE E:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 931.513GB SYSTEM_FREEDISC_SPACE 762.977GB
SYSTEM_DIRECTX_VERSION DirectX 11
SYSTEM_GRAPHICS NVIDIA GeForce GTX 570
SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY1
SYSTEM_GRAPHICS_CHIP GeForce GTX 570
SYSTEM_GRAPHICS_MAKER NVIDIA
SYSTEM_GRAPHICS_VRAM 1232.438 MB
SYSTEM_GRAPHICS_SHARED_VRAM 1775.570 MB
SYSTEM_GRAPHICS_DAC Integrated RAMDAC
SYSTEM_GRAPHICS_DISPLAY_MODE 1920 x 1080 (32 bit) (144Hz)
SYSTEM_GRAPHICS_DRIVER nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
SYSTEM_GRAPHICS_DRIVER_VERSION 9.18.0013.3788
SYSTEM_GRAPHICS_DRIVER_DATE 20-05-2014 10:44:03
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
SYSTEM_GRAPHICS_PIXEL_SHADER 3.0
SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
SYSTEM_GRAPHICS NVIDIA GeForce GTX 570
SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY2
SYSTEM_GRAPHICS_CHIP GeForce GTX 570
SYSTEM_GRAPHICS_MAKER NVIDIA
SYSTEM_GRAPHICS_VRAM 1232.438 MB
SYSTEM_GRAPHICS_SHARED_VRAM 1775.570 MB
SYSTEM_GRAPHICS_DAC Integrated RAMDAC
SYSTEM_GRAPHICS_DISPLAY_MODE 1920 x 1080 (32 bit) (60Hz)
SYSTEM_GRAPHICS_DRIVER nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
SYSTEM_GRAPHICS_DRIVER_VERSION 9.18.0013.3788
SYSTEM_GRAPHICS_DRIVER_DATE 20-05-2014 10:44:03
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
SYSTEM_GRAPHICS_PIXEL_SHADER 3.0
SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
SYSTEM_SOUND Speakers (High Definition Audio Device)
SYSTEM_SOUND_DEVICE_ID {C3430D0F-D0F2-466F-806B-0363C90853C3}
SYSTEM_SOUND_DEVICE_NAME HdAudio.sys
SYSTEM_SOUND_DRIVER_VERSION 6.01.7601.17514
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 21-11-2010 11:23:47
SYSTEM_SOUND Digital Audio (S/PDIF) (High Definition Audio Device)
SYSTEM_SOUND_DEVICE_ID {0F18B903-7EBA-4744-AAA5-6A8C40D2D282}
SYSTEM_SOUND_DEVICE_NAME HdAudio.sys
SYSTEM_SOUND_DRIVER_VERSION 6.01.7601.17514
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 21-11-2010 11:23:47
SYSTEM_SOUND Digital Audio (S/PDIF) (High Definition Audio Device)
SYSTEM_SOUND_DEVICE_ID {874769EA-3527-40A1-B1CA-36F89E5430A5}
SYSTEM_SOUND_DEVICE_NAME HdAudio.sys
SYSTEM_SOUND_DRIVER_VERSION 6.01.7601.17514
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 21-11-2010 11:23:47
SYSTEM_SOUND Headphones (High Definition Audio Device)
SYSTEM_SOUND_DEVICE_ID {DBAC7BF8-BE23-4E64-A5D6-54BD03FC290C}
SYSTEM_SOUND_DEVICE_NAME HdAudio.sys
SYSTEM_SOUND_DRIVER_VERSION 6.01.7601.17514
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 21-11-2010 11:23:47
SYSTEM_INPUT {6F1D2B60-D5A0-11CF-BFC7444553540000}
SYSTEM_INPUT_NAME Mouse
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 3 SYSTEM_GAMEPAD_BUTTON 8 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {6F1D2B61-D5A0-11CF-BFC7444553540000}
SYSTEM_INPUT_NAME Keyboard
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 109 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE58150-6733-11E3-8001444553540000}
SYSTEM_INPUT_NAME Controller (XBOX 360 For Windows)
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 5 SYSTEM_GAMEPAD_BUTTON 10 SYSTEM_GAMEPAD_FOV 1
SYSTEM_INPUT {CDE61D90-6733-11E3-8002444553540000}
SYSTEM_INPUT_NAME Microsoft Hardware USB Mouse
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 1 SYSTEM_GAMEPAD_BUTTON 1024 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE707F0-6733-11E3-8003444553540000}
SYSTEM_INPUT_NAME Micr
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE72F00-6733-11E3-8004444553540000}
SYSTEM_INPUT_NAME Micr
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 1280 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE72F00-6733-11E3-8005444553540000}
SYSTEM_INPUT_NAME Micr
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE75610-6733-11E3-8006444553540000}
SYSTEM_INPUT_NAME Micr
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 256 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE75610-6733-11E3-8007444553540000}
SYSTEM_INPUT_NAME USB Receiver
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 652 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE88E90-6733-11E3-8008444553540000}
SYSTEM_INPUT_NAME USB Receiver
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 3 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE8B5A0-6733-11E3-8009444553540000}
SYSTEM_INPUT_NAME USB Receiver
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE8B5A0-6733-11E3-800A444553540000}
SYSTEM_INPUT_NAME Cordless Receiver
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE8DCB0-6733-11E3-800B444553540000}
SYSTEM_INPUT_NAME Cordless Receiver
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE951E0-6733-11E3-800C444553540000}
SYSTEM_INPUT_NAME Cordless Device
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 652 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE951E0-6733-11E3-800D444553540000}
SYSTEM_INPUT_NAME Cordless Device
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 3 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {CDE951E0-6733-11E3-800E444553540000}
SYSTEM_INPUT_NAME Љ
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0

Browser Information
- Name and version of the browser currently in-use: Internet Explorer 10
- Internet Explorer Version: Internet Explorer 10.0.9200.16921

Pictures