Since we are constantly rolling out updates to our software, the Blogsy app may be currently configured for the old configuration.
I have heard of other users having some minor issues (if you consider many italics post "minor") using Blogsy, but as they reported the issue to Blogsy, they were very responsive and deployed fixes quickly. So I would recommend going ahead and making contact to report the bug you're seeing.
To fix the posts, I recommend going into your blog not via the app and visiting your posts in the Edit Post page (switch to "text" from "visual") and stripping out the unnecessary italics. Or you should also be able to do this in the visual editor by highlight the text and clicking on the Italic icon to remove it.
Let me know if you have a problem doing this and I'll help you. I'm sorry we can't do more!