Adsense tokens "[adsense:XxY:SlotID]" in node content aren't being replaced by ads
Wow, finally solved. Since pages are rendered via Panels the solution was to check "Clean" option from Panel content manager to the node body which removes "dangerous" markup.

In other words it seems like node body doesn't respect text format settings when rendered via Panels. Or at least not all of it without checking this option.