Cntrl-C sometimes does not copy selected text to clipboard

[Laraul]

Time: 7:20 PM (MST)
Frequency: Frequently
World name: Hyperion
Character name: Laraul Lunacy
NPC name: N/A
Monster name: N/A
Class/Level:BRD/50
Party or solo:Solo
In-game time:???
Area and coordinates: Uldah Inn
Steps:
1. Select a line of text from log window.
2. Press Ctrl-C to copy selected text to clipboard
3. Press Ctrl-V to paste.
4. Repeat until Ctrl-V pastes prior selection.

PC Specs
2010 MacPro running Windows 8.1 Pro.