Accessing the Emscripten cache at "...emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it

I have this error consistently when building a large project (https://github.com/dotnet/runtimelab/blob/feature/NativeAOT-LLVM) after clearing the emscripten `cache` What can I do to try to diagnose the problem? There seems to be caches in both the emsdk tree and in my user profile (this is windows). How can I know which of the caches is getting blocked and where the deadlock, if any is occuring?

FWIW this is a portion of the log
```
[31/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_idna.c.o
cache : error : Accessing the Emscripten cache at "E:\GitHub\emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "E:\GitHub\emsdk\upstream\emscripten\cache\cache.lock" and try again. If this occurs deterministically, consider filing a bug. [E:\GitHub\runtimelab\src\libraries\Native\build-native.proj]
[32/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_casing.c.o
cache : error : Accessing the Emscripten cache at "E:\GitHub\emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "E:\GitHub\emsdk\upstream\emscripten\cache\cache.lock" and try again. If this occurs deterministically, consider filing a bug. [E:\GitHub\runtimelab\src\libraries\Native\build-native.proj]
[33/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_localeStringData.c.o
cache : error : Accessing the Emscripten cache at "E:\GitHub\emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "E:\GitHub\emsdk\upstream\emscripten\cache\cache.lock" and try again. If this occurs deterministically, consider filing a bug. [E:\GitHub\runtimelab\src\libraries\Native\build-native.proj]
[34/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_localeNumberData.c.o
cache : error : Accessing the Emscripten cache at "E:\GitHub\emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "E:\GitHub\emsdk\upstream\emscripten\cache\cache.lock" and try again. If this occurs deterministically, consider filing a bug. [E:\GitHub\runtimelab\src\libraries\Native\build-native.proj]
[35/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_calendarData.c.o
cache : error : Accessing the Emscripten cache at "E:\GitHub\emsdk\upstream\emscripten\cache" is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "E:\GitHub\emsdk\upstream\emscripten\cache\cache.lock" and try again. If this occurs deterministically, consider filing a bug. [E:\GitHub\runtimelab\src\libraries\Native\build-native.proj]
[36/41] Building C object System.Globalization.Native/CMakeFiles/System.Globalization.Native-Static.dir/pal_collation.c.o
```

Perhaps relevant is that ICU and zlib ports are being built .

Emcc version
```
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 2.0.33 (0e68b98e85a1644a7224c360fa6cb21bea5dc33d)
```