In the latest snapshot 14w04b when placing a map in an item frame, it enlarges the item frame like normal, but the map will be invisible, leaving you with a large item frame but with no visible map in it. Also, blocks don't appear to be in the correct orientation/position or rendered correctly when placed in item frames, and they appear to be only half showing. And when I loaded up my world in this snapshot, all of my item frames that I had previously placed in the previous snapshot and were fine; flew off the wall, though I think that is because they have a new redstone ability so the game was "updating" them, albeit in a strange way. Nevertheless, they are not working correctly with maps or most items.
Duplicate of MC-45764 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.
Other bug mentioned is a duplicate of MC-45453.
EDIT: Please submit only one bug per issue.