Istio-proxy segfault/crash in istio::control::http::RequestHandlerImpl::Report()

Hi,

We are seeing the following backtrace being generated occasionally from our istio-proxy sidecar:

[Envoy (Epoch 0)] [2021-07-10 10:20:59.733][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:83] Caught Segmentation fault, suspect faulting address 0x5617b2c793f0
[Envoy (Epoch 0)] [2021-07-10 10:20:59.733][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:70] Backtrace (use tools/stack_decode.py to get line numbers):
[Envoy (Epoch 0)] [2021-07-10 10:20:59.733][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:71] Envoy version: a7b2578494d79fe098f0e99282e0236946562fa0/1.12.0/Clean/RELEASE/BoringSSL
[Envoy (Epoch 0)] [2021-07-10 10:20:59.734][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #0: __restore_rt [0x7f6ad6ff9890]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.742][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #1: istio::control::http::RequestHandlerImpl::Report() [0x5617abebe1f0]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.751][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #2: Envoy::Http::Mixer::Filter::log() [0x5617abe6e9bb]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.758][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #3: Envoy::Http::ConnectionManagerImpl::ActiveStream::~ActiveStream() [0x5617ad010405]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.766][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #4: Envoy::Http::ConnectionManagerImpl::ActiveStream::~ActiveStream() [0x5617ad010aee]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.773][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #5: Envoy::Event::DispatcherImpl::clearDeferredDeleteList() [0x5617acdf7d23]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.780][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #6: event_process_active_single_queue [0x5617ad1025e6]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.788][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #7: event_base_loop [0x5617ad100f9e]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.796][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #8: Envoy::Server::WorkerImpl::threadRoutine() [0x5617acdf0ad8]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.805][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #9: Envoy::Thread::ThreadImplPosix::ThreadImplPosix()::$_0::__invoke() [0x5617ad28ad23]
[Envoy (Epoch 0)] [2021-07-10 10:20:59.805][27][critical][backtrace] [bazel-out/k8-opt/bin/external/envoy/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:75] #10: start_thread [0x7f6ad6fee6db]

Any clues on what this might be triggered by? We have verified that this happens under no or minimal load passing through the proxy.

Thanks!