lldb from OpenBSD ports failed to launch or debug any program

I've installed a newly OpenBSD (current). I've installed llvm and lldb packages. When trying to debug a program, /usr/local/bin/lldb failed to launch or debug the process, but /usr/bin/lldb works fine. I'm using the lldb package because I want to test python scripting.

After installing OpenBSD, these are the commands that reproduce the problem with lldb:

obsdtest$ uname -a
OpenBSD obsdtest.thelinuxkitten.home 6.9 GENERIC#433 amd64
obsdtest$ sysctl -n kern.version
OpenBSD 6.9-beta (GENERIC) #433: Wed Mar 31 18:35:11 MDT 2021
    deraadt@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC
obsdtest$ su -
obsdtest# pkg_add -v llvm lldb
obsdtest# exit
obsdtest$ echo "#include <stdio.h>\nint main(int argc, char *argv[])\n{\n    printf(\"Hi OpenBSD.\\\n\");\n    return 0;\n}\n" > hiobsd.c
obsdtest$ /usr/local/bin/clang -g hiobsd.c
obsdtest$ whereis -a lldb
/usr/bin/lldb
/usr/local/bin/lldb
obsdtest$ lldb -b -o 'process launch' a.out 
(lldb) target create "a.out"
Current executable set to '/home/kitten/a.out' (x86_64).
(lldb) process launch
Hi OpenBSD.
Process 45195 exited with status = 0 (0x00000000) 

Process 45195 launched: '/home/kitten/a.out' (x86_64)
obsdtest$ /usr/local/bin/lldb -b -o 'process launch' a.out 
(lldb) target create "a.out"
Current executable set to '/home/kitten/a.out' (x86_64).
(lldb) process launch
error: failed to launch or debug process
obsdtest$ 

After reading the lldb documentation, I don't know what might be happening, or what I'm doing wrong.

Thanks in advance.