For some reason, in IE/FF it seems to float to the LEFT of the RIGHT EDGE of the feature image in the posts. This puts the bar in the middle of the content.
My theme is Suffusion although I have seen this in Thesis as well.
My temporary work around was to put a 1x1 gif as the first thing in the post so the bar can float to the left of that.
This has been exceedingly aggravating.