Why are compiled kernel modules contents in `/lib/modules/$KERNEL_VERSION-microsoft-standard-WSL2` being reset repeatly

I am learning eBPF and try to install bcc in WSL environment. I follow the official document to compile the kernel module manually, then install BCC from source, and after

sudo mount -t debugfs debugfs /sys/kernel/debug

I attempt to run some bcc examples and tools and they all work well. But after some time or after restart of the WSL, these bcc programs can not work any more with errors like

chdir(/tmp/kheaders-5.15.146.1-microsoft-standard-WSL2): No such file or directoryTraceback (most recent call last):  File "./opensnoop", line 289, in <module>    b = BPF(text='')  File "/usr/lib/python3/dist-packages/bcc-0.29.1+008ea09e-py3.8.egg/bcc/__init__.py", line 479, in __init__Exception: Failed to compile BPF module <text>

and I find the installed contents in /lib/modules/$KERNEL_VERSION-microsoft-standard-WSL2 are reset, with totally different file modification time. I need to manually install the kernel modules again to make the bcc programs work well again.

Comparison of the contents of /lib/modules/$KERNEL_VERSION-microsoft-standard-WSL2:

fresh:

lrwxrwxrwx 1 root root     38 Apr  2 20:05 build -> /MY_BUILD_PATH/WSL2-Linux-Kerneldrwxr-xr-x 4 root root     80 Apr  2 20:05 kernel-rw-r--r-- 1 root root  58136 Apr  2 20:05 modules.alias-rw-r--r-- 1 root root  59354 Apr  2 20:05 modules.alias.bin-rw-r--r-- 1 root root  15144 Apr  2 20:05 modules.builtin-rw-r--r-- 1 root root  44804 Apr  2 20:05 modules.builtin.alias.bin-rw-r--r-- 1 root root  17273 Apr  2 20:05 modules.builtin.bin-rw-r--r-- 1 root root 111270 Apr  2 20:05 modules.builtin.modinfo-rw-r--r-- 1 root root    619 Apr  2 20:05 modules.dep-rw-r--r-- 1 root root   1150 Apr  2 20:05 modules.dep.bin-rw-r--r-- 1 root root      0 Apr  2 20:05 modules.devname-rw-r--r-- 1 root root    434 Apr  2 20:05 modules.order-rw-r--r-- 1 root root     55 Apr  2 20:05 modules.softdep-rw-r--r-- 1 root root   1286 Apr  2 20:05 modules.symbols-rw-r--r-- 1 root root   1294 Apr  2 20:05 modules.symbols.binlrwxrwxrwx 1 root root     38 Apr  2 20:05 source -> /MY_BUILD_PATH/WSL2-Linux-Kernel

stale:

dr-xr-xr-x 1 root root   4096 Mar 23 11:21 kernel-r-xr-xr-x 1 root root  58136 Jan 11 04:27 modules.alias-r-xr-xr-x 1 root root  59354 Jan 11 04:27 modules.alias.bin-r-xr-xr-x 1 root root  15144 Jan 11 04:27 modules.builtin-r-xr-xr-x 1 root root  44804 Jan 11 04:27 modules.builtin.alias.bin-r-xr-xr-x 1 root root  17273 Jan 11 04:27 modules.builtin.bin-r-xr-xr-x 1 root root 111270 Jan 11 04:27 modules.builtin.modinfo-r-xr-xr-x 1 root root    619 Jan 11 04:27 modules.dep-r-xr-xr-x 1 root root   1150 Jan 11 04:27 modules.dep.bin-r-xr-xr-x 1 root root      0 Jan 11 04:27 modules.devname-r-xr-xr-x 1 root root    434 Jan 11 04:27 modules.order-r-xr-xr-x 1 root root     55 Jan 11 04:27 modules.softdep-r-xr-xr-x 1 root root   1286 Jan 11 04:27 modules.symbols-r-xr-xr-x 1 root root   1294 Jan 11 04:27 modules.symbols.bin

2 directory links build and source disappear.

My environment:

Ubuntu 20.04.6 LTS,kernel 5.15.146.1-microsoft-standard-WSL2,in WSL2,Windows 10 enterprise, 22H2, 19045.4170

I do not understand why. Any guidance?