turbKSP crashes for certain flow conditions

Description

Using turbKSP ("ANKUseTurbDADI": False) can cause optimizations to crash seemingly randomly with the following error:

[106]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[106]PETSC ERROR: Argument out of range
[106]PETSC ERROR: Inserting a new blocked indexed nonzero block (1231606, 1253914) into matrix
[106]PETSC ERROR: See https://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[106]PETSC ERROR: Petsc Release Version 3.15.1, Jun 17, 2021
[106]PETSC ERROR: #1 MatSetValuesBlocked_MPIBAIJ() at packages/petsc-3.15.1/src/mat/impls/baij/mpi/mpibaij.c:427
[106]PETSC ERROR: #2 MatSetValuesBlocked() at packages/petsc-3.15.1/src/mat/interface/matrix.c:1866
 ---------------------------------------------------------------------------
PETSc or MPI Error. Error Code 63. Detected on Proc **
Error at line:   644 in file: adjointUtils.F90
 ---------------------------------------------------------------------------

The reason for this is not clear, especially because this occurs in the middle of optimizations and analyses in previous iterations work fine.

Code versions

• PETSc: 3.15

Start by reproducing the crash with turbKSP enabled via ANKUseTurbDADI=False, then inspect adjointUtils.F90 around line 644 and the PETSc matrix operation in the failing optimization iteration. Compare the flow conditions and matrix indices with successful iterations. Done means the reported conditions no longer produce the PETSc or MPI error, with a regression check if the project provides one.