I am experiencing a random glitch where my dynamic panels cut in half when I preview. I have had this same issue happen on multiple occasions on multiple different mock-ups. I use the latest version of Google Chrome to preview.
It makes it difficult to design when every time I try to view a dynamic panel, only half of the content is showing. The only workaround I have found is if I close out of the Axure project and re-open it, I can view the panel correctly again. Unfortunately, as soon as I refresh the page the panel breaks again.
In previous prototypes, I found that if I ignore the issue and continue working, it tends to fix itself eventually somehow. Regardless, I thought you should be aware of this annoying bug.