i just found a funny bug in slic3r, in my old settings i had the scale set to .75 for the last print. but i forgot about it when i pulled that old setting into the new version, even though its scale was set to 1 it printed out at .75 scale.
i thought it was a funny bug, but i thought i should let ya know
Yes, it's a known behavior with legacy config files. Some settings such as scale, rotate, duplicate, duplicate_grid are going to be removed from config files.