Time: Varies; noted during raids of Final Coil Turn 1 @ 5-8PM PST
Frequency: Sometimes
World name:Excalibur
Character name: Shirin Saekuverit
Race: Midlander Female
Class/Level: SCH 50
Party or solo: Party
In-game Time: Varies
Area and coordinates: Final Coil Turn 1, possible in other areas as well
Monster Name: Imdugud (may be possible in other battles)
Steps:
1. Begin with one party member, other than yourself, targeted.
2. Click another player's name in the party window.
3. Immediately (within a half-second of target switching but after mouse input) begin casting a direct heal ability (effect most noted with Adloquium).
4. If bug occurs, the previous target will receive the effect of the spell, including HP restoration and shield, despite the new target being clearly targeted and the spell having been activated after the click went out.

Connection Specs
- Type of internet connection/provider: Fiber-optic 25Mbit/s up/down, connected via LAN cable, serviced by Frontier Communications
- Modem maker/model number: Actiontec MI424-WR Rev. F

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

SYSTEM_OS Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.141211-1742)
SYSTEM_CPU Intel(R) Core(TM) i5 CPU 760 @ 2.80GHz (4 CPUs), ~2.8GHz
SYSTEM_CORE_NUM SYSTEM_CORE_LOGIC 4 SYSTEM_CORE_PHYSICS 4
SYSTEM_BIOS BIOS Date: 07/22/10 16:12:13 Ver: 08.00.15
SYSTEM_LANGUAGE English (Regional Setting: English)
SYSTEM_MEMORY 4062.051MB
SYSTEM_VIRTUAL_MEMORY 2047.875MB
SYSTEM_PAGE_FILE 8122.285MB
SYSTEM_STORAGE C:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 223.471GB SYSTEM_FREEDISC_SPACE 27.142GB
SYSTEM_STORAGE E:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 931.511GB SYSTEM_FREEDISC_SPACE 116.978GB
SYSTEM_DIRECTX_VERSION DirectX 11
SYSTEM_GRAPHICS NVIDIA GeForce GTX 460
SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY1
SYSTEM_GRAPHICS_CHIP GeForce GTX 460
SYSTEM_GRAPHICS_MAKER NVIDIA
SYSTEM_GRAPHICS_VRAM 978.438 MB
SYSTEM_GRAPHICS_SHARED_VRAM 1775.025 MB
SYSTEM_GRAPHICS_DAC Integrated RAMDAC
SYSTEM_GRAPHICS_DISPLAY_MODE 1920 x 1200 (32 bit) (59Hz)
SYSTEM_GRAPHICS_DRIVER nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
SYSTEM_GRAPHICS_DRIVER_VERSION 9.18.0013.1422
SYSTEM_GRAPHICS_DRIVER_DATE 3/14/2013 9:53:06 PM
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
SYSTEM_GRAPHICS_PIXEL_SHADER 3.0
SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
SYSTEM_SOUND Speakers (Realtek High Definition Audio)
SYSTEM_SOUND_DEVICE_ID {B9CD1C3F-0D88-4F70-8C12-FDFEFB09A298}
SYSTEM_SOUND_DEVICE_NAME RTKVHD64.sys
SYSTEM_SOUND_DRIVER_VERSION 6.00.0001.6037
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 1/28/2010 10:48:44 PM
SYSTEM_SOUND Realtek Digital Output(Optical) (Realtek High Definition Audio)
SYSTEM_SOUND_DEVICE_ID {177E7604-8341-4EAE-9DFF-00C93BDE8281}
SYSTEM_SOUND_DEVICE_NAME RTKVHD64.sys
SYSTEM_SOUND_DRIVER_VERSION 6.00.0001.6037
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 1/28/2010 10:48:44 PM
SYSTEM_SOUND Realtek Digital Output (Realtek High Definition Audio)
SYSTEM_SOUND_DEVICE_ID {830BFFF2-F8D6-4534-AA6C-5D477A944C71}
SYSTEM_SOUND_DEVICE_NAME RTKVHD64.sys
SYSTEM_SOUND_DRIVER_VERSION 6.00.0001.6037
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 1/28/2010 10:48:44 PM
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 128 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {93577090-582D-11E2-8002444553540000}
SYSTEM_INPUT_NAME Steelseries Consumer
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 64 SYSTEM_GAMEPAD_FOV 0
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Additional note:
- This is most noticeable in Final Coil Turn 1, where the requirement for rapid target-switching and shielding to block Prey is present (and the bug's unpredictable-but-persistant nature makes that Turn extremely frustrating) but I believe the bug can be reproduced anywhere.