You may have hit an issue that sneaked in our service pack - we changed the casing of the two icon fonts in Kendo UI Mobile, but due to a caching issue in our build system, both new and old fonts made it in the release archive. That would not be a problem by itself if all OS file systems were case-sensitive which they are not (except in Linux). So when you (or the installer) extract the files, the fonts overwrite each other and only 2 of them remain - one new and one old. Depending on in what browser are you testing, this may lead to missing icons. The fix is easy - download the latest internal build and extract the 2 fonts from the images folder in your images folder, overwriting the ones you have there (or delete them beforehand).
I'm attaching the 2 fonts here, just in case.
Let me know if this helps.
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