I see, the rules had a grey spot.

It wasn't mentioned what counts as an "official nomination".
There must be a way to make a nomination official.
What makes one's nomination official?

I wouldn't say the current custom isn't the right way, because the correct way wasn't explicitly mentioned in the rules. Because it isn't/wasn't mentioned in the rules at all, I'd say follow the current conduct of doing things until this grey spot has been fixed.

But the rules cannot be altered without referendum, so I'd say delete the altered bit, stick with current custom... or have a really urgent community chat if you want to change the custom. As the custom has been formed in a long period of time, I don't think it should be changed just like that, when it has achieved a position of being considered as a official rule, without even being so.

Just my two cents, and I really mean two cents, as I'm not an expert and not even very active in these forums, not to mention I'm not any figure of authority in this matter. So feel free to ignore my post, I've not meant to insult anyone with my take on this.