It might not have a detent at every quadrature state but it sure must "go thru" them.
Oh definitely. I even see them display on the LCD when I turn my encoder REAL slow.

That's why I had put this comment in my code, to show the CW/CCW progression through the wiper states:

Code:
'  Wiper Chart:
'  ============
'     A   B
'    --- ---
'     0   0
'     1   0  /\ CCW
'     1   1
'     0   1  \/ CW
'     0   0
'
' Careful, EC11 30 detents 15 pulses will move from 00 to 11
'          EC11 20 detents can move from 00 back to 00 in one click

No wonder my older EC11 were causing me so much grief in my initial testing.