Why do you claim that it is not working ?
It is working perfectly fine with -m 12500 = RAR3-hp
The hash even has the signature ($RAR3$*0*) that makes it very clear that no other mode than -m 12500 should be used.
Here are all the example hashes: https://hashcat.net/wiki/example_hashes
It should be very easy to see that the "hash" should start with "$RAR3$*0*" (for mode -m 12500, without the quotes) and that there are no file names etc within the "hash".
It is working perfectly fine with -m 12500 = RAR3-hp
The hash even has the signature ($RAR3$*0*) that makes it very clear that no other mode than -m 12500 should be used.
Here are all the example hashes: https://hashcat.net/wiki/example_hashes
It should be very easy to see that the "hash" should start with "$RAR3$*0*" (for mode -m 12500, without the quotes) and that there are no file names etc within the "hash".