IME Character input to ListElement causes List to be destroyed

Steps to reproduce:
1. Focus into editable TextArea with a list element (eg Bulleted list) in its TextFlow.
2. Place cursor at first position within list element
3. insert a DBCS character using IME (User reported issue using Korean as example)

Actual Results:
List is destroyed and character appears as first character on line

Expected Results:
List remains, character is entered as first character after bullet

Workaround (if any):
None