UE 5.1: Metahuman's hair disappears when rendering alpha

Hi all.

Is it currently possible to render a MH char with hair + alpha channel in UE 5.1?

In my image sequence renders, the hair is only present for a few of the frames.
The scene only contains a skylight, directional light , point light and a MH char with LOD 0 hair.

I’m using the previously working deferred rendering/includes alpha/actor layer workflow so is this a bug specific in 5.1 or am I missing a new setting somewhere?

Thanks!

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I Have the same Proplem Pls Hit me up if you find a solution that would be so helpful…

Update:

It turns out that , for my scene, a stencil layer is unnecesssary to render a MH char with hair + alpha channel.

When a scene only contains a MH char and lights, you just need to enable “accumulates alpha” and render to png or exr sequence. You don’t need to add the char to a layer.

The char will render with an alpha channel and without any missing hair issues and the background will be transparent.

Unfortunately, the vanishing hair on stencil layers issue is still present in UE 5.2 but hopefully it will be fixed at some point.

Problem seems to be known, but currently on the backlog. So vote for it I guess? Although the developer notes mention that is a motion blur problem only? Unreal Engine Issues and Bug Tracker (UE-175577)

Can you please write down your steps to achieve your transparent bg with MRQ?

SOLUTION!
I changed the hair >> rendering>> Advanced>> Bound Scale from 1 to 2.