Is there anyway to have this work on your input?
Say you have an alembic going into your asset the output simply ignores the timeshift node.

Is the Alembic file read in the Maya side? If so, then it's probably a limitation of Houdini Engine, regardless of whether the geometry data is from Alembic or not. When nodes cook inside Houdini Engine, they only have access to input parameters and geometries at a single time. So any nodes that involve getting data *outside the asset* at a different time won't work.

Depending on your use case, if the timeshift only needs to go back in time, then you might be able to workaround the limitation by using a Cache SOP. The idea is to have the cache SOP store the geometries from the previous frames. So that when subsequent nodes require a earlier frame, the previous frames are available inside the Cache SOP, and the node doesn't need to get geometries from the Maya side.

Note that if the Alembic file read is inside the asset, then it should just work, because all the data is self-contained inside the asset. The limitation only happens when the asset needs to pull data from the host application (i.e. Maya).

I see, thanks.