Just doing a bit of debugging this morning. It looks like style 2a works because it is an older file that references the googleapis using http instead of https. This fails, and actually prevents the ads from loading.
In style 2, the non-secure link to google's apis is commented out and replaced with some script which dynamically loads google's scripts via https.
I suspect if the google scripts were loaded in the same way, style 2a would show the same issue.
As for the actual issue, it's tough slogging through compressed javascript, even with Chrome's pretty-printer. One lead is that I can see a certain property (_breakglass_mode_) is being set to 2. If it is instead set to 1, the left-margin is created properly (as a relative value, instead of an absolute value). Alternatively, if the owning object for that property is not created at all, no left-margin is computed and the ad is in the correct place. So far as I can see, when the ad is in the correct location, it's because the owning object is not created in the first place.
I'm taking a break, but will try to look again later today.