This affected `Mesh Deform`, `Corrective Smooth` and `Laplacian Smooth`.
Exposed by 57ea827bfb (e5ec04d73c).
Evaluating the incoming mesh can be different in
`BKE_object_handle_data_update` as opposed to
`object_force_modifier_update_for_bind` due to different
`CustomData_MeshMasks` being used (the former used a handpicked set, the
later was still using `CD_MASK_BAREMESH`). But since moving many
relevant [to modifiers] data to attributes, this could lead to binding go
wrong (e.g. reporting a vertex count mismatch as reported in #110021
which was due to the fact that creases were not propagated and that
changed the output [also vertex count] of a subdivision modifier in the
stack).
Now use `CD_MASK_DERIVEDMESH` in `object_force_modifier_update_for_bind`
to get all relevant attributes for evaluation (this is not used in `BKE_object_handle_data_update`
to avoid a big performance impact there).
Also fixes#109626 afaict.
Should probably go into 3.6 LTS (maybe even 3.3 LTS).
Pull Request: https://projects.blender.org/blender/blender/pulls/110095
2cb9290012