I run a self-hosted blog (www.tidinessproject.co.za) on the Coraline theme. When viewed on a mobile phone in the full version of the site (as opposed to the mobile version) my tag cloud (which is housed in the Primary Widget area) appears superimposed over the header of the blog. This has been observed on a Blackberry Z10 (had a complaint from a reader) and on my own Samsung S3. The mobile version looks great, though!
I use the sidebar-content-sidebar layout.
Apologies if this has been covered before - I figure I can probably self-fix it by moving the tag cloud somewhere else, but thought it would be worth reporting in case some one else has the same problem.
I have a screenshot of the problem (mailed to me by the reader) which I can supply if need be.