To be fair, not sure if this is intentional or not. It doesn't say when you are blocking someone that YOU can't still message them. Though I do think that if you block someone it should go both ways. Would like to see what the community thinks though.
Roman, are you checking the right place for blocks? Go to inbox at the top, go to block list to the right and check? Cause there is also in the other block list for direct messages.