The original version of the game had the standees of the characters cut oval in shape which allowed for more of them to fit on the tokens. With this new edition, they went to the much nicer looking clear acrylic standees, but kept the original artwork, which is why they look like that.
To unbend them, you can try getting them warm with a hair dryer and then bending them into the position you want (Straight) and run them under cold water while holding them in place and it should set them straight. I should not that I've never actually tried this method with these tokens as mine were not bent, but I have used this method with great success on other types of standees and miniatures.
The original version of the game and its expansions all used cardboard standees. It wasn't until the AEG reprint of the game where the components were upgraded to the clear plastic ones.