FIREking, I have re-saved files of my own, etc...and double-clicked them & checked headers myself, for the bug reported, my icon files are perfectly fine, but aren't working, if your files aren't correct in some way & re-saving is working for you, that's fine, but it's not working for me, considering the header isn't messed up to begin with.
Try making a change to the file (add a blank icon state).
I also noticed that icons with just one single icon_state would not load on input().
Anyways yes, it opens with dream maker(to edit the icon, it doesn't corrupt the header...) this is intended behavior.