It appears that MC on Mac sometimes crashes when changing the directories with the following message "Warning: cannot change directory..." and the directory change does happen but the pannels of the MC shift and if you continue it just get really ugly and unreadable.
After doing some investigation I have found the cause of the problem - it is the "_" (undescore) character in the directory names. It seems whenever you are trying to go into directories that contain the underscores the subshell behind mc cannot do it. So the MC pannels show the directory listings but the warning appears as well (which refers to the subshell error).
There are two solutions at the moment:
Use mc with -u option to disable the subshell like so: mc -u
or rename your directories so that they do not include this evil character that spoils the lives or Mac users.
Hope this helps...