You are the first to report such a problem and unfortunately I am not aware of it. In order to help you we will need detailed steps-by-step instructions along with screenshots showing how to reproduce the problem.
By default the spellchecker uses the Phonetic spellcheck provider, but my suggestion is to change it to EditDistance provider and see whether the problem still persists. You can see the following help article for more information: Improper Spelling Suggestions.
the Telerik team