We saw the following assert twice, once with jdk25 in July, now with jdk26 in October. Both times on Windows x86_64, fastdebug binaries.
Btw the output of the assert is bad and should be changed, it cuts off the double numbers and so it hides the real values and the error (the output suggests that everything is correct and GC pause time == accounted_ms ).

jdk26
test gc/arguments/TestTargetSurvivorRatioFlag.java triggered it

# Internal Error (d:\priv\jenkins\ci2\client-home\workspace\openjdk-jdk-windows_x86_64-dbg\jdk\src\hotspot\share\gc\g1\g1GCPhaseTimes.cpp:571), pid=8976, tid=24744
# assert(_gc_pause_time_ms >= accounted_ms) failed: GC pause time(0.001ms) cannot be smaller than the sum of each phase(0.001ms).

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x7f4005] public: void __cdecl G1GCPhaseTimes::print(bool) __ptr64+0x3d5 (no source info available)
V [jvm.dll+0x84c152] public: void __cdecl G1YoungCollector::collect(void) __ptr64+0x702 (no source info available)
V [jvm.dll+0x7a5fb5] private: void __cdecl G1CollectedHeap::do_collection_pause_at_safepoint(unsigned __int64) __ptr64+0x175 (no source info available)
V [jvm.dll+0x84b129] public: virtual void __cdecl VM_G1CollectForAllocation::doit(void) __ptr64+0x39 (no source info available)
V [jvm.dll+0x127f70b] public: void __cdecl VM_Operation::evaluate(void) __ptr64+0xdb (no source info available)
V [jvm.dll+0x1281565] private: void __cdecl VMThread::evaluate_operation(class VM_Operation * __ptr64) __ptr64+0xe5 (no source info available)
V [jvm.dll+0x1281dfb] private: void __cdecl VMThread::inner_execute(class VM_Operation * __ptr64) __ptr64+0x23b (no source info available)
V [jvm.dll+0x1282214] public: virtual void __cdecl VMThread::run(void) __ptr64+0x114 (no source info available)
V [jvm.dll+0x11cbc51] public: void __cdecl Thread::call_run(void) __ptr64+0x1c1 (no source info available)
V [jvm.dll+0xe46484] thread_native_entry+0xc4 (no source info available)
C [ucrtbase.dll+0x1fb80] (no source info available)
C [KERNEL32.DLL+0x84d4] (no source info available)
C [ntdll.dll+0x51a11] (no source info available)


jdk25 (from July)
test compiler/runtime/Test6826736.java triggered it

# Internal Error (d:\priv\jenkins\client-home\workspace\openjdk-25u-weekly-windows_x86_64-dbg\jdk\src\hotspot\share\gc\g1\g1GCPhaseTimes.cpp:574), pid=36268, tid=12524
# assert(_gc_pause_time_ms >= accounted_ms) failed: GC pause time(0.000ms) cannot be smaller than the sum of each phase(0.000ms).

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x7f0247] G1GCPhaseTimes::print+0x3e7 (g1GCPhaseTimes.cpp:573)
V [jvm.dll+0x847c98] G1YoungCollector::collect+0x708 (g1YoungCollector.cpp:1153)
V [jvm.dll+0x7a1254] G1CollectedHeap::do_collection_pause_at_safepoint_helper+0xa4 (g1CollectedHeap.cpp:2496)
V [jvm.dll+0x846cd7] VM_G1CollectForAllocation::doit+0x37 (g1VMOperations.cpp:122)
V [jvm.dll+0x125351b] VM_Operation::evaluate+0xdb (vmOperations.cpp:75)
V [jvm.dll+0x125533a] VMThread::evaluate_operation+0xba (vmThread.cpp:283)
V [jvm.dll+0x1255cdb] VMThread::inner_execute+0x23b (vmThread.cpp:429)
V [jvm.dll+0x12560f4] VMThread::run+0x114 (vmThread.cpp:176)
V [jvm.dll+0x11a0924] Thread::call_run+0x1b4 (thread.cpp:248)
V [jvm.dll+0xe2a001] thread_native_entry+0xe1 (os_windows.cpp:562)
C [ucrtbase.dll+0x2268a] (no source info available)
C [KERNEL32.DLL+0x17ac4] (no source info available)
C [ntdll.dll+0x5a8c1] (no source info available)