sceUtilityLoadNetModule, audio and thread issue

I have noticed a problem with sceUtilityLoadNetModule.

If I load PSP_NET_MODULE_COMMON and PSP_NET_MODULE_INET and then I call pspAudioInit(), I will not be able to create a thread with sceKernelCreateThread. If a thread already exists in my game, it will be stopped.
sceKernelCreateThread will always return a negative thread id.

sceUtilityLoadNetModule(PSP_NET_MODULE_COMMON);
sceUtilityLoadNetModule(PSP_NET_MODULE_INET);

pspAudioInit();
SceUID thd_id = sceKernelCreateThread("thread1", thread1, 0x38, 0x10000, 0, NULL);
if (thd_id >= 0)
{
    sceKernelStartThread(thd_id, 0, 0);
}
else
{
    pspDebugScreenPrintf("Bad thread id\n");
}

This should prints Bad thread id.

I don't have a PSP 2000/3000 to test but I have the problem on my PSP 1000 and Street. My FW version is 6.61.
I think there is an issue with sceUtilityLoadNetModule or something else about network because most of network samples do not work on my PSP 1000, see: https://github.com/pspdev/pspsdk/issues/45#issuecomment-1611225348

Small compilable sample code with the issue (there is a precompiled EBOOT too): No_Thread_Issue.zip

Start by building and running the attached No_Thread_Issue.zip sample on the reported PSP 1000 or Street setup with firmware 6.61. Trace the sequence through sceUtilityLoadNetModule, pspAudioInit, and sceKernelCreateThread, then compare it with the linked network-sample discussion. Done means identifying the cause and verifying that the sample can create and start its thread after audio and network initialization.