A problem like JDK-8351921 has occurred again despite the fix:

# Internal Error (d:\client-home\workspace\openjdk-jdk-dev-windows_x86_64-dbg\jdk\src\hotspot\share\gc\g1\g1CollectedHeap.cpp:2640), pid=37480, tid=35604
# assert(!hr->has_pinned_objects()) failed: must not free a region which contains pinned objects

V [jvm.dll+0x71cda4] G1CollectedHeap::free_region+0x1b4 (g1CollectedHeap.cpp:2639)
V [jvm.dll+0x7c5af4] FreeCSetClosure::do_heap_region+0x2b4 (g1YoungGCPostEvacuateTasks.cpp:809)
V [jvm.dll+0x720502] G1CollectedHeap::par_iterate_regions_array+0x132 (g1CollectedHeap.cpp:2016)
V [jvm.dll+0x728b0c] G1CollectionSet::par_iterate+0x3c (g1CollectionSet.cpp:159)
V [jvm.dll+0x7c650e] G1PostEvacuateCollectionSetCleanupTask2::FreeCollectionSetTask::do_work+0x8e (g1YoungGCPostEvacuateTasks.cpp:905)
V [jvm.dll+0x70bc75] G1BatchedTask::work+0x125 (g1BatchedTask.cpp:95)
V [jvm.dll+0x10a42a7] WorkerThread::run+0x97 (workerThread.cpp:200)
V [jvm.dll+0xfb11b4] Thread::call_run+0x1b4 (thread.cpp:236)
V [jvm.dll+0xd74991] thread_native_entry+0xe1 (os_windows.cpp:566)
C [ucrtbase.dll+0x2268a] (no source info available)
C [KERNEL32.DLL+0x17ac4] (no source info available)
C [ntdll.dll+0x5a8c1] (no source info available)