I have today's nightly installed (January 11th 2014) after not updating the Nighlty builds since october and noticed an issue when you want to change ISO settings from the ML menu.
The advantage by changing ISOs from the ML menu is obvious, because you can set ISO to intermediate values like 160, 320 and so on.
Now, when you click or scroll to the left to get directly to the highest value of the ISO settings and then try to go back to the lowest or Auto setting by clicking or scrolling right, it doesn't work anymore, both LV and Canon GUI.
Gets stuck at the highest value, BUT only if you have ISO expansion activated from the Canon Custom Functions. The issue doesn'T happen when ISO expansion is turned off or if you change ISO by pressing the Iso button of the camera before (works both in LV and Canon GUI)
When ISO expansion is turned off you can skip through ISO settings both ways in ML menu.
Tested on my Canon EOS 550D