Weird Hair Behavior After Render It happened once before with another project and It was related to a keyframe that was messing around with the hair somehow but now, I can't see any keyframe in the Dope sheet.

After I try to render though, the hair are messed up in the viewport and everything goes back to normal whenever I move the timeline slider. This Is why I found strange it doesn't seem to be related to a keyframe..

It's a messy hair job for now anyway and doing it all again will not be a whole day waster but I'm posting in case something like this happens at a more crucial time of a project.

Thanks

Hair Normal


Hair Render Preview


Render mess up


Aftermath of render
You have different resolution of mesh in preview and render:



This may not be so important, but not for edited hair. In fact, you have two different mesh. So move Particle system before Subsurf, or make Subdivision setting same for preview and render