I think it is because of the Blogger's "Dynamic Views" template your blog uses. Maybe another (more classic) template would be better for cross-device compatibility.
Indeed, ideally as part of such a move, they'd enhance G+ a bit[1] to cover the areas where it's currently weaker than blogger. Then everybody would win...
[1] E.g. better support for formatting articles; curently it only supports a rather pathetic subset of markdown.