kspsolve demo failure for odd process number: PETSc.Vec.copy Incompatible vector local lengths

Did something break the API in PETSc 3.13.6? I'm trying to rebuild petsc4py 3.13.0 against PETSc 3.13.6, but demo kspsolve is failing on Debian unstable. The test log reports:

make -C kspsolve
make[1]: Entering directory '/tmp/autopkgtest.PjzB4v/build.REL/real-tree/test-demos/kspsolve'
mpiexec -n 5 python3 test_mat_cg.py
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
iterations: 46 residual norm: 0.000303767
Traceback (most recent call last):
  File "test_mat_cg.py", line 43, in <module>
    x.copy(u)
  File "PETSc/Vec.pyx", line 432, in petsc4py.PETSc.Vec.copy
petsc4py.PETSc.Error: error code 75
[3] VecCopy() line 1556 in /build/petsc-VkXITk/petsc-3.13.6+dfsg1/src/vec/vec/interface/vector.c
[3] Arguments are incompatible
[3] Incompatible vector local lengths parameter # 1 local size 205 != parameter # 2 local size 192
Traceback (most recent call last):
  File "test_mat_cg.py", line 43, in <module>
    x.copy(u)
  File "PETSc/Vec.pyx", line 432, in petsc4py.PETSc.Vec.copy
petsc4py.PETSc.Error: error code 75
[4] VecCopy() line 1556 in /build/petsc-VkXITk/petsc-3.13.6+dfsg1/src/vec/vec/interface/vector.c
[4] Arguments are incompatible
[4] Incompatible vector local lengths parameter # 1 local size 204 != parameter # 2 local size 192
Traceback (most recent call last):
  File "test_mat_cg.py", line 43, in <module>
    x.copy(u)
  File "PETSc/Vec.pyx", line 432, in petsc4py.PETSc.Vec.copy
petsc4py.PETSc.Error: error code 75
[1] VecCopy() line 1556 in /build/petsc-VkXITk/petsc-3.13.6+dfsg1/src/vec/vec/interface/vector.c
[1] Arguments are incompatible
[1] Incompatible vector local lengths parameter # 1 local size 205 != parameter # 2 local size 224
Traceback (most recent call last):
  File "test_mat_cg.py", line 43, in <module>
    x.copy(u)
  File "PETSc/Vec.pyx", line 432, in petsc4py.PETSc.Vec.copy
petsc4py.PETSc.Error: error code 75
[2] VecCopy() line 1556 in /build/petsc-VkXITk/petsc-3.13.6+dfsg1/src/vec/vec/interface/vector.c
[2] Arguments are incompatible
[2] Incompatible vector local lengths parameter # 1 local size 205 != parameter # 2 local size 192
Traceback (most recent call last):
  File "test_mat_cg.py", line 43, in <module>
    x.copy(u)
  File "PETSc/Vec.pyx", line 432, in petsc4py.PETSc.Vec.copy
petsc4py.PETSc.Error: error code 75
[0] VecCopy() line 1556 in /build/petsc-VkXITk/petsc-3.13.6+dfsg1/src/vec/vec/interface/vector.c
[0] Arguments are incompatible
[0] Incompatible vector local lengths parameter # 1 local size 205 != parameter # 2 local size 224

Do we know what to do about this error?