Mesh refinement + mesh modification + prism6 does not create expected variable continuity

[GiudGiud]

Description

When running a 2 hex cell with top cell being refined, a classic pressure on top problem, anchor on bottom produces the expected solution in the regular case and when there is a mesh modifier that switches the subdomain assignments between the initial mesh and the mesh on which the BC is applied
With prisms, the solution is not right in that second case.
The solution is right without any block restriction on displacements

Note that in some configuration (when moving all elements to subdomain 1), the activation of the BC causes a seg fault. Unclear why at the moment

How to reproduce

Run this input with solid mechanics:

[Problem]
  kernel_coverage_check = false
  material_coverage_check = false
  boundary_restricted_node_integrity_check = false
  boundary_restricted_elem_integrity_check = false
[]

new_domain_blocks = '1001 1001'

[Mesh]
  [box]
    type = FileMeshGenerator
    file = msh.msh
  []

  [refine]
    type = RefineBlockGenerator
    input = box
    block = '2'
    refinement = '1'
    # enable_neighbor_refinement = false
  []

  add_subdomain_ids = '${new_domain_blocks}'
[]


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
[]

[Variables]
  [disp_x]
    block = '${new_domain_blocks}'
  []
  [disp_y]
    block = '${new_domain_blocks}'
  []
  [disp_z]
    block = '${new_domain_blocks}'
  []
[]

# ===== Tensor mechanics for all active domain blocks =====
[Physics]
  [SolidMechanics]
    [QuasiStatic]
      [all]
        strain = finite
        add_variables = false
        block = '${new_domain_blocks}'
        generate_output = 'stress_xx stress_zz'
      []
    []
  []
[]

# ===== Gravity =====
[Kernels]
  # [n1]
  #   type = NullKernel
  #   block = '1 2'
  #   variable = disp_x
  # []
  # [n2]
  #   type = NullKernel
  #   block = '1 2'
  #   variable = disp_y
  # []
  # [n3]
  #   type = NullKernel
  #   block = '1 2'
  #   variable = disp_z
  # []
  [Gravity1]
    type = BodyForce
    block = '${new_domain_blocks}'
    use_displaced_mesh = false
    variable = disp_z
    value = -10
  []
[]

# ===== Boundary Conditions =====
[BCs]
  [archor_x]
    type = DirichletBC
    boundary = '3'
    variable = disp_x
    value = 0
  []

  [archor_y]
    type = DirichletBC
    boundary = '3'
    variable = disp_y
    value = 0
  []

  [archor_z]
    type = DirichletBC
    boundary = '3'
    variable = disp_z
    value = 0
  []

  [dz]
    type = FunctionNeumannBC
    boundary = '4'
    variable = disp_z
    function = '-2e3 * (t - 200)'
  []
[]

# ===== Materials (linear-elastic to keep it simple) =====
[Materials]
  [elasticity_tensor1]
    type = ComputeIsotropicElasticityTensor
    block = '${new_domain_blocks}'
    youngs_modulus = 50E6 # 50 MPa
    poissons_ratio = 0.3
  []

  [stress]
    type = ComputeFiniteStrainElasticStress
    block = '${new_domain_blocks}'
  []

  [density1]
    type = GenericConstantMaterial
    block = '${new_domain_blocks}'
    prop_names = density
    prop_values = 2000
  []
[]

[MeshModifiers]
  [m1]
    type = TimedSubdomainModifier
    times = '100 100'
    blocks_from = '1 2'
    blocks_to = ${new_domain_blocks}
    execute_on = 'TIMESTEP_BEGIN'
  []
[]

[Controls]
  [c1]
    type = TimePeriod
    enable_objects = 'BCs::dz'
    start_time = '200'
  []
[]

# ===== Executioner =====
[Executioner]
  type = Transient

  end_time = 600
  dt = 100

  solve_type = 'PJFNK'
  petsc_options = '-snes_converged_reason'

  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type -pc_hypre_boomeramg_max_iter'
  petsc_options_value = '  201               hypre    boomeramg      10'

  nl_abs_tol = 5E-9
  nl_max_its = 400

  l_tol = 1E-8
  l_max_its = 200
[]

[Outputs]
  exodus = true
[]

Impact

Wrong results

Discussed in #29079

^{Originally posted by PEI0214 November 14, 2024}

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Question

Hello,
When I use mesh refinement and MeshModifiers together, the following happens. This doesn't seem normal. When the grid is 8-node cells, this phenomenon does not occur.

Grid and result

The 6-node grid and results are as follows:

The 8-node grid and results are as follows:

The setting of boundary conditions and mesh refinement are the same. It's all full restraint on the bottom and pressure on the top. Why does this happen?