Help with monster sprites

did you try changing the Mould used for the formation of the new enemy you are putting in? Each sprite in the formation will normally cut off at the mould, sometimes if you have more than one enemy, there may not be a proper mould to fully show both enemies. since you're only changing one enemy, try using FF3usME V6.5 to go the monster formation that you're editing, and click "Show" it should be a checkbox just below "Mould Used" in General at the top, if the sprite exceeds that mould, change it to one that will fit it, hope this helps.