Can Adsense not recognice the same ads

Same ads in different size

[jetteroheller]

I have in the left navigation a 300x250 and below the content a 336x280 ad block.

It happens often, that both blocks show the same image ad.

Can Adsense not recognize the same graphic in different sizes?

What's the experience with the same ad size?

Happens 2 times the same ad also, when both blocks are the same size?

[explorador]

I bet they do recognize diff sizes of the same ad. I've seen the same on my sites and all those times is about a campaign of the advertiser (kinda aggressive campaign). It seems like they were targeting my sites as a whole.

In my case is very rare, I would say exclusively with graphic ads. I read about it somewhere (perhaps at jen's) and it was mentioned as a problem already solved, so that's why I bet they do recognize dif sizes, they are just showing them for some reason I don't know yet. Sorry if my post is not very informative I just tell you the trend I've seen.