What do you mean, "spam"? I got this (and I was happy to) because I'm subscribed to their official channels. If you don't want to receive it, maybe you should unsubscribe to their channels. Or do you mean something else?

I mean that when I signed up for Telegram I never checked any boxes agreeing to recieve marketeing materials. Since signing up for Telegram I have not joined any channels or done anything that could be interpreted as consent to recieving marketing materials. And regardless the sent me spam about this (via the same channel that they sent me a code I needed to login to a second device).

It came from the service notifications channel, aka the same one that you get login tokens from.

It's one message though, I personally don't mind.

Could you share a screenshot please?

I'm very surprised by this. To me the bot that sends me the login tokens does only that. I received this because I subscribed to an official channel named Telegram News where they share this.

If they're sending news thru the login bot to people who aren't subscribed to news, that's not nice behaviour of them in my view.

I'm also Telegram news channel subscriber... No unwanted notification anywhere (as far as I notice, that is what I care)

This was my only and immediate reaction. It was a serious faux pas.

Maybe they just got excited to share it, I dunno.

Maybe it's signalling in preparation for their ICO.