Having written a test for this, I see that the test fails on Darwin platforms as well.

With my FreeBSD thread WIP I see the same failure in test_state_after_breakpoint_with_dwarf.

What is odd is that I don't even see SBThread::IsStopped() getting called.

I enabled logging to run the test:
export LLDB_LOG="lldb_unit_test.log"
export LLDB_LOG_OPTION="api step process thread event expr state"

and in the log I see:
SBDebugger(0x80159b600)::GetSelectedTarget () => SBTarget(0x80b696100): a.out
SBTarget(0x80b696100)::GetProcess () => SBProcess(0x801736000)
SBProcess(0x801736000)::GetNumThreads () => 1
SBProcess(0x801736000)::GetThreadAtIndex (index=0) => SBThread(0x80b701e00)
SBTarget(0x80b696100)::GetProcess () => SBProcess(0x801736000)
SBProcess(0x801736000)::GetTarget () => SBTarget(0x80b696100)
SBTarget(0x80b696100)::GetExecutable () => SBFileSpec(0x80b6abb20)
SBFileSpec(0x80b6abb20)::GetPath (dst_path="/tank/emaste/src/llvm/tools/lldb/test/functionalities/thread/state/a.out", dst_len=1024) => 72
SBProcess(0x801736000)::GetState () => stopped
SBProcess(0x801736000)::GetNumThreads () => 1

I can confirm that the GetThreadAtIndex (index=0) call corresponds to the python test code "thread = process.GetThreadAtIndex(0)"

So I think it may actually be that the SWIG / python interface has some issue rather than the thread's state actually being incorrect.

*** Bug llvm/llvm-bugzilla-archive#25081 has been marked as a duplicate of this bug. ***

Another test failing in the same way on FreeBSD now:

======================================================================
FAIL: test_state_after_continue_dwarf (TestThreadStates.ThreadStateTestCase)
Test thread state after continue.

Traceback (most recent call last):
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2263, in dwarf_test_method
return attrvalue(self)
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 608, in wrapper
func(*args, **kwargs)
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 608, in wrapper
func(*args, **kwargs)
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/functionalities/thread/state/TestThreadStates.py", line 34, in test_state_after_continue
self.thread_state_after_continue_test()
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/functionalities/thread/state/TestThreadStates.py", line 141, in thread_state_after_continue_test
self.wait_for_running_event()
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/functionalities/thread/state/TestThreadStates.py", line 106, in wait_for_running_event
lldbutil.expect_state_changes(self, listener, [lldb.eStateRunning])
File "/tank/emaste/src/llvm/tools/lldb/packages/Python/lldbsuite/test/lldbutil.py", line 750, in expect_state_changes
test.assertEqual(expected_state, got_state)
AssertionError: 6 != 4
Config=x86_64-/usr/bin/clang

Ran 5 tests in 6.281s

RESULT: FAILED (0 passes, 1 failures, 0 errors, 0 skipped, 4 expected failures, 0 unexpected successes)

[TestThreadStates.py FAILED]

*** Bug llvm/llvm-bugzilla-archive#28455 has been marked as a duplicate of this bug. ***

reported fixed on FreeBSD in https://reviews.llvm.org/D90757

mentioned in issue llvm/llvm-bugzilla-archive#25081

mentioned in issue llvm/llvm-bugzilla-archive#28455