Josh may be right about the mislabel. But ply's funny like that.
Depending on where it's from (You never said where you purchased it,
but it sounded like the borg), 3/4 is more like 23/32nds, 1/2 is around
15/32nds (or 12 mm, now I'm getting confused). Bring a tape measure in
with you the next time. You'll be surprised at the variables, even from
sheet to sheet, sometimes. Tom