I have plenty of stroke on my optimizer, but the head is on the lowest position.

Last time I ran into this isue with another bow/sight combo it was hard for me not to think the drop away was dropping too soon, allowing the arrow to shoot "down" towards the target instead of a more level starting point.
Removing length from the draw cord proved this to be true (my point of impact went up the longer the arrow was supported).

Not too sure you could check this with a MZE.

I doubt with Mathews "level nock travel" this would be too much of an issue, unless the cam isn't timed properly that is.