MU* Pose Style ( using ':' instead of '/me') fails when the text starts with a (non standard American) special character resulting in the ':' not being removed from the chat line.
Those characters are language specific but used as first character in thousands of possible words.
Characters I've tried so far include: é è ê ç ä ö ü И ï ǎ ق and more.
Example:
shows in chat as
Workaround:
Use '/me' which works for all characters.
My system:
Cool VL Viewer 1.25.0 (23) (Linux)