Do You think This Is Bad Manners?

I have a relative... who I won't name, even though they are unlikely to read this but you never know. So anyway I have a relative, whose wife had a birthday a couple of weeks ago. Now we haven't seen them since before the birthday and so we haven't been able to give her her present yet.
However the relative went up to another relative of mine, who we had recently visited, and asked if we had left the present with them.

Now we had never mentioned a present, we hadn't told them there was a present to be collected at some point. They just assumed there was a present to be had. Which my immediate family and I think is really really rude.

This relative does this a lot. If you dare to forget their anniversary or something, or you post your card and it is late, they become almost unbearable. I would never go up to someone and say 'where's my present?' But they do. My Dad said a few years ago he told the relative that you don't ask things like that. To which the relative replied 'I do'.

Just to show how different two sides of a family can be. A couple of years ago when my sister turned 17 the aforementioned relative said that they would give her some money as a present the following week. And then they forgot. And we have never mentioned it. Well we moaned about it amongst ourselves. And it came up again as a conversation topic due to this recent incident. But we never actually went up to them and told them that they owed my sister a present.

You could understand if they were children. Children say what they think. They could be forgiven for that. But given that the wife is 9 years older than me and the relative is 18 years older then me... and I am 26... well what do you think about it?

Is it rude of them or should we be hammering on their door demanding my sister's 17th birthday present?