Markdown1.1 does not parse emphasis in the middle of a word correctly

If emphasis is used in the middle of the word, it is not parsed correctly.

Case 1:

*test*user says yes.

testuser
 

result: "test*user says yes" is surrounded by <em>. testuser normal

Case 2:

*test*user says yes.(followed by two spaces)  
testuser

result: everything in emphasis

Case 3:

*test*user says yes.*
testuser

result: "test*user says yes." italic, testuser normal

Is this supposed to be a feature?