How to reproduce:

Unzip the attached “IN-149620“ project
In the project folder, open the terminal window and start the mock cache server with the command: “python repro/mock_accelerator.py --port 10999 --rst-after 2000000 --stall 3”
In the project folder, open a new terminal window and regenerate the asset contents of the project with this command: “python repro/generate_assets.py <project-path> --seed <any-new-number>” (make sure to change the placeholder variables)
In the project folder, open a new terminal window and run the Editor with this command: “<path to unity exe> -batchmode -projectPath <project-path> -enableCacheServer -cacheServerEndpoint 127.0.0.1:10999 -cacheServerNamespacePrefix repro3449941 -cacheServerEnableDownload false -cacheServerEnableUpload true -executeMethod ReproWait.Run -logFile repro-run.log” (make sure to change the placeholder variables)
Wait for ~5 minutes and open the generated “repro-run.log” file with a text editor
Observe the result at the end of the “repro-run.log” file

Actual result: Outputted logs show a crash
Expected result: Outputted logs show failed uploads and a reconnect attempt but the Editor does not crash

Reproducible with: 6000.0.0f1, 6000.0.80f1, 6000.3.21f1
Not reproducible with: 6000.5.0a7, 6000.5.6f1, 6000.6.0b6, 6000.7.0a3
Fixed in: 6000.6.0a1 (b0e692525f04)

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Notes:

The python scripts used in the reproduction are located in the “repro“ folder inside the project folder
Reproduction requires Python 3.9 and above to be installed on the system
In step 4, ReproWait keeps the Editor alive ~260 s and triggers a fresh upload wave every 25 s; each wave gives the mock another mid-upload disconnect

First few lines of the stack traces:
0x00007FFC5649AC40 (Unity) TcpProtobufSession::SendMessageAsync
0x00007FFC5649AFDF (Unity) TcpProtobufClient::SendMessageBatchedAsync
0x00007FFC563562C0 (Unity) AcceleratorClient::InternalGet
0x00007FFC563533D8 (Unity) <lambda_7e811f046b6344c0b6557af44dbdfa77>::operator()
0x00007FFC5647370E (Unity) asio::detail::completion_handler<core::mutable_function<void __cdecl(void)>,asio::io_context::basic_executor_type<std::allocator<void>,0> >::do_complete

0x00007FFC55F869DB (Unity) TcpProtobufClient::EndBatch
0x00007FFC55E4080F (Unity) <lambda_4943dcd2926113e32680dfec7ad01928>::operator()
0x00007FFC55F61E3E (Unity) asio::detail::completion_handler<core::mutable_function<void __cdecl(void)>,asio::io_context::basic_executor_type<std::allocator<void>,0> >::do_complete
0x00007FFC55F4F7FA (Unity) asio::detail::win_iocp_io_context::do_one
0x00007FFC55F50A44 (Unity) asio::detail::win_iocp_io_context::run