nvfortran -acc: ASSOCIATE construct in a parallel loop ends in CUDA_ERROR_ILLEGAL_ADDRESS

! # Draft finding: acc34-w-associate on nvhpc
!
! - compiler: nvhpc
! - toolchain: nvhpc; arch: sm_80; machine: wingtip; memory mode: copy; opt: -O2
! - program: catalog acc34-w-associate (f90, version 34, sha256 68f44e65e61fcf01)
! - expected: check=pass (trusted; elision + model)
! - actual: run_error  (exit_status: 1) [the confirmer's class run_error; the matrix's class of the same run is wrong_answer: a run
!   that fails]
! - observed: the run ends with "call to cuStreamSynchronize returned error 700 (CUDA_ERROR_ILLEGAL_ADDRESS)" (NVHPC 25.11
!   and 26.9): an ASSOCIATE construct in a parallel loop; the OpenMP form (omp52-w-associate) is correct
! - verdict: compiler_bug by rule R20-runtime-bug: a legal program fails at run time, deterministically, against an expected value
!   from two or more independent sources with an executed witness, and another toolchain, mode, arch or the elision gives the
!   expected value
! - reason: expected trusted check=pass (elision + model): stored main verdict: elision + model agree; witnesses: cce19/gfx942/copy,
!   cce20/gfx942/copy, cce21/gfx942/copy, elision
! - citations: RUL-DERIVED-NEEDS-EXECUTION (rulings.md); RUL-WITNESS-PER-MODE (rulings.md);
!   RUL-SAME-COMPILER-RUNS (rulings.md); RUL-PRESENCE-WITNESS (rulings.md); RUL-METAMORPHIC-OTHER-FAMILY
!   (rulings.md)
! - legality: legal: offload.engine.prerun.check accepts it (rerun: offload.engine.rules with the
!   race rule and the restriction checks, and the AFAR flang front end, not under test here); no
!   compiler under test, gfortran or gcc is a legality witness
! - witnesses: cce19/gfx942/copy, cce20/gfx942/copy, cce21/gfx942/copy, elision
! - withdrawn: none
!
! Generated by compliance.widen (OpenACC 3.4, free-form Fortran; catalog widening). Do not edit.
! id: acc34-w-associate
! primary atom: base.device.associate
! atoms: base.device.associate
! legal: yes
! observable: yes
! ran_on_host: inside the compute region of interest (acc_on_device)
! evidence: construct
! needs: none
! std: f2008
! feature: an ASSOCIATE construct in device code
! spec: OpenACC 3.4 §1.8, p.16: Fortran 2008 is a normative base language (the features whose use is unspecified are listed there;
! this is not one of them)
program wide_prog
  use openacc, only: acc_device_host, acc_on_device
  implicit none
  integer, parameter :: n = 64
  integer :: a(n), b(n), ref(n)
  integer :: i, host_flag
  logical :: ok
  do i = 1, n
    a(i) = i
    b(i) = 0
    ref(i) = 2*i + 1
  end do
  host_flag = 1
  !$acc parallel loop copyin(a) copyout(b) copy(host_flag)
  do i = 1, n
    associate (x => a(i), y => b(i))
      y = 2*x + 1
    end associate
    if (i == 1) host_flag = merge(1, 0, acc_on_device(acc_device_host))
  end do
  ok = all(b == ref)
  print '(a,i0,a,a)', 'RESULT ran_on_host=', host_flag, ' check=', merge('pass', 'fail', ok)
end program wide_prog