removeKey API - Getting 500 error status code, when trying to remove certificate

When using removePassword API to remove a certificate password, a 500 status code was thrown.

 

However, I've managed to remove the certificate and its associate password via removeKey API, 

 

My question is, getting 500 error code is expected here!?

It's somehow misleading, isn't 4xx - Client Error more informative since it's a bad request from my side (the requester) not MS back-end.

 

Thank you!