2.76 hair bug ?

I got some strange behaviour with hair, and i wonder if this is a bug.
But before i do a bugpost i wondered have other people also experienced “bad hairdays” (as in johny bravo)

While in edit mode the hair looks fine cambed and reasonable, but some strange squares in it.
My hair material, uses hair input node to decide if its hair strand or not, if not it renders transparant (so shouldnt render a square). The hair itself is a hair mesh (copy from head mesh with several faces removed).

The bottem image… well looks like before cambing how i wake up… but its the same model only the cambing doesnt seam to have worked ??

Even some more detail, the hair was devided into 3 vertex groups with eacht their own hair emitter so i could camb it more easily; which is a normal way of creating hair, this trick is commonly used.

did you check preview/render setting in the particle system panel?

where is that option inside the hair system?..

what i showed rightside was the render tab, just to show they are equal., in edit mode the hair looks good, like how it was cambed.

Found it, its not a bug.

Since i used hair groups, for sides, i didnt notice the mesh had an unwanted modifier in.
I had still a subdiv modifier in place as from the original head.
But i discovered it a bit late so i had it allready remade.

Hello I think I have big problems with hair particles system too.
I made a hair particles system for the hairs of my character.
So I have children and parents.
Everything is good.
But when I animate my character, make him following a path, my hair particles get crazy.
More precisely, ONLY children get crazy, not the parents.
In addition, I already put the armature modifier just above hair particles system.
And I checked use modifier stack.
Do you have any idea?